MongoDB Atlas With Terraform - Cluster and Backup Policies
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In this tutorial, I will show you how to create a MongoDB cluster in Atlas using Terraform. We saw in a previous article how to create an API key to start using Terraform and create our first project module. Now, we will go ahead and create our first cluster. If you don't have an API key and a project, I recommend you look at the previous article.
This article is for anyone who intends to use or already uses infrastructure as code (IaC) on the MongoDB Atlas platform or wants to learn more about it.
Everything we do here is contained in the provider/resource documentation: mongodbatlas_advanced_cluster | Resources | mongodb/mongodbatlas | Terraform
At this point, we will create our first replica set cluster using Terraform in MongoDB Atlas. As discussed in the previous article, Terraform is a powerful infrastructure-as-code tool that allows you to manage and provision IT resources in an efficient and predictable way. By using it in conjunction with MongoDB Atlas, you can automate the creation and management of database resources in the cloud, ensuring a consistent and reliable infrastructure.
Before we begin, make sure that all the prerequisites mentioned in the previous article are properly configured: Install Terraform, create an API key in MongoDB Atlas, and set up a project in Atlas. These steps are essential to ensure the success of creating your replica set cluster.
The first step is to configure the Terraform provider for MongoDB Atlas. This will allow Terraform to communicate with the MongoDB Atlas API and manage resources within your account. Add the following block of code to your provider.tf file:
1 provider "mongodbatlas" {}
In the previous article, we configured the Terraform provider by directly entering our public and private keys. Now, in order to adopt more professional practices, we have chosen to use environment variables for authentication. The MongoDB Atlas provider, like many others, supports several authentication methodologies. The safest and most recommended option is to use environment variables. This implies only defining the provider in our Terraform code and exporting the relevant environment variables where Terraform will be executed, whether in the terminal, as a secret in Kubernetes, or a secret in GitHub Actions, among other possible contexts. There are other forms of authentication, such as using MongoDB CLI, AWS Secrets Manager, directly through variables in Terraform, or even specifying the keys in the code. However, to ensure security and avoid exposing our keys in accessible locations, we opt for the safer approaches mentioned.
Inside the versions.tf file, you will start by specifying the version of Terraform that your project requires. This is important to ensure that all users and CI/CD environments use the same version of Terraform, avoiding possible incompatibilities or execution errors. In addition to defining the Terraform version, it is equally important to specify the versions of the providers used in your project. This ensures that resources are managed consistently. For example, to set the MongoDB Atlas provider version, you would add a
required_providers block inside the Terraform block, as shown below:1 terraform { 2 required_version = ">= 0.12" 3 required_providers { 4 mongodbatlas = { 5 source = "mongodb/mongodbatlas" 6 version = "1.14.0" 7 } 8 } 9 }
After configuring the version file and establishing the Terraform and provider versions, the next step is to define the cluster resource in MongoDB Atlas. This is done by creating a .tf file, for example main.tf, where you will specify the properties of the desired cluster. As we are going to make a module that will be reusable, we will use variables and default values so that other calls can create clusters with different architectures or sizes, without having to write a new module.
I will look at some attributes and parameters to make this clear.
1 # ------------------------------------------------------------------------------ 2 # MONGODB CLUSTER 3 # ------------------------------------------------------------------------------ 4 resource "mongodbatlas_advanced_cluster" "default" { 5 project_id = data.mongodbatlas_project.default.id 6 name = var.name 7 cluster_type = var.cluster_type 8 backup_enabled = var.backup_enabled 9 pit_enabled = var.pit_enabled 10 mongo_db_major_version = var.mongo_db_major_version 11 disk_size_gb = var.disk_size_gb 12
In this first block, we are specifying the name of our cluster through the name parameter, its type (which can be a
REPLICASET, SHARDED, or GEOSHARDED), and if we have backup and point in time activated, in addition to the database version and the amount of storage for the cluster.1 advanced_configuration { 2 fail_index_key_too_long = var.fail_index_key_too_long 3 javascript_enabled = var.javascript_enabled 4 minimum_enabled_tls_protocol = var.minimum_enabled_tls_protocol 5 no_table_scan = var.no_table_scan 6 oplog_size_mb = var.oplog_size_mb 7 default_read_concern = var.default_read_concern 8 default_write_concern = var.default_write_concern 9 oplog_min_retention_hours = var.oplog_min_retention_hours 10 transaction_lifetime_limit_seconds = var.transaction_lifetime_limit_seconds 11 sample_size_bi_connector = var.sample_size_bi_connector 12 sample_refresh_interval_bi_connector = var.sample_refresh_interval_bi_connector 13 }
Here, we are specifying some advanced settings. Many of these values will not be specified in the .tfvars as they have default values in the variables.tf file.
Parameters include the type of read/write concern, oplog size in MB, TLS protocol, whether JavaScript will be enabled in MongoDB, and transaction lifetime limit in seconds. no_table_scan is for when the cluster disables the execution of any query that requires a collection scan to return results, when true. There are more parameters that you can look at in the documentation, if you have questions.
1 replication_specs { 2 num_shards = var.cluster_type == "REPLICASET" ? null : var.num_shards 3 4 dynamic "region_configs" { 5 for_each = var.region_configs 6 7 content { 8 provider_name = region_configs.value.provider_name 9 priority = region_configs.value.priority 10 region_name = region_configs.value.region_name 11 12 electable_specs { 13 instance_size = region_configs.value.electable_specs.instance_size 14 node_count = region_configs.value.electable_specs.node_count 15 disk_iops = region_configs.value.electable_specs.instance_size == "M10" || region_configs.value.electable_specs.instance_size == "M20" ? null : region_configs.value.electable_specs.disk_iops 16 ebs_volume_type = region_configs.value.electable_specs.ebs_volume_type 17 } 18 19 auto_scaling { 20 disk_gb_enabled = region_configs.value.auto_scaling.disk_gb_enabled 21 compute_enabled = region_configs.value.auto_scaling.compute_enabled 22 compute_scale_down_enabled = region_configs.value.auto_scaling.compute_scale_down_enabled 23 compute_min_instance_size = region_configs.value.auto_scaling.compute_min_instance_size 24 compute_max_instance_size = region_configs.value.auto_scaling.compute_max_instance_size 25 } 26 27 analytics_specs { 28 instance_size = try(region_configs.value.analytics_specs.instance_size, "M10") 29 node_count = try(region_configs.value.analytics_specs.node_count, 0) 30 disk_iops = try(region_configs.value.analytics_specs.disk_iops, null) 31 ebs_volume_type = try(region_configs.value.analytics_specs.ebs_volume_type, "STANDARD") 32 } 33 34 analytics_auto_scaling { 35 disk_gb_enabled = try(region_configs.value.analytics_auto_scaling.disk_gb_enabled, null) 36 compute_enabled = try(region_configs.value.analytics_auto_scaling.compute_enabled, null) 37 compute_scale_down_enabled = try(region_configs.value.analytics_auto_scaling.compute_scale_down_enabled, null) 38 compute_min_instance_size = try(region_configs.value.analytics_auto_scaling.compute_min_instance_size, null) 39 compute_max_instance_size = try(region_configs.value.analytics_auto_scaling.compute_max_instance_size, null) 40 } 41 42 read_only_specs { 43 instance_size = try(region_configs.value.read_only_specs.instance_size, "M10") 44 node_count = try(region_configs.value.read_only_specs.node_count, 0) 45 disk_iops = try(region_configs.value.read_only_specs.disk_iops, null) 46 ebs_volume_type = try(region_configs.value.read_only_specs.ebs_volume_type, "STANDARD") 47 } 48 } 49 } 50 }
At this moment, we are placing the number of shards we want, in case our cluster is not a REPLICASET. In addition, we specify the configuration of the cluster, region, cloud, priority for failover, autoscaling, electable, analytics, and read-only node configurations, in addition to its autoscaling configurations.
1 dynamic "tags" { 2 for_each = local.tags 3 content { 4 key = tags.key 5 value = tags.value 6 } 7 } 8 9 bi_connector_config { 10 enabled = var.bi_connector_enabled 11 read_preference = var.bi_connector_read_preference 12 } 13 14 lifecycle { 15 ignore_changes = [ 16 disk_size_gb, 17 ] 18 } 19 }
Next, we create a dynamic block to loop for each tag variable we include. In addition, we specify the BI connector, if desired, and the lifecycle block. Here, we are only specifying
disk_size_gb for an example, but it is recommended to read the documentation that has important warnings about this block, such as including instance_size, as autoscaling can change and you don't want to accidentally retire an instance during peak times.1 # ------------------------------------------------------------------------------ 2 # MONGODB BACKUP SCHEDULE 3 # ------------------------------------------------------------------------------ 4 resource "mongodbatlas_cloud_backup_schedule" "default" { 5 project_id = data.mongodbatlas_project.default.id 6 cluster_name = mongodbatlas_advanced_cluster.default.name 7 update_snapshots = var.update_snapshots 8 reference_hour_of_day = var.reference_hour_of_day 9 reference_minute_of_hour = var.reference_minute_of_hour 10 restore_window_days = var.restore_window_days 11 12 policy_item_hourly { 13 frequency_interval = var.policy_item_hourly_frequency_interval 14 retention_unit = var.policy_item_hourly_retention_unit 15 retention_value = var.policy_item_hourly_retention_value 16 } 17 18 policy_item_daily { 19 frequency_interval = var.policy_item_daily_frequency_interval 20 retention_unit = var.policy_item_daily_retention_unit 21 retention_value = var.policy_item_daily_retention_value 22 } 23 24 policy_item_weekly { 25 frequency_interval = var.policy_item_weekly_frequency_interval 26 retention_unit = var.policy_item_weekly_retention_unit 27 retention_value = var.policy_item_weekly_retention_value 28 } 29 30 policy_item_monthly { 31 frequency_interval = var.policy_item_monthly_frequency_interval 32 retention_unit = var.policy_item_monthly_retention_unit 33 retention_value = var.policy_item_monthly_retention_value 34 } 35 }
Finally, we create the backup block, which contains the policies and settings regarding the backup of our cluster.
This module, while detailed, encapsulates the full functionality offered by the
mongodbatlas_advanced_cluster and mongodbatlas_cloud_backup_schedule resources, providing a comprehensive approach to creating and managing clusters in MongoDB Atlas. It supports the configuration of replica set, sharded, and geosharded clusters, meeting a variety of scalability and geographic distribution needs.One of the strengths of this module is its flexibility in configuring backup policies, allowing fine adjustments that precisely align with the requirements of each database. This is essential to ensure resilience and effective data recovery in any scenario. Additionally, the module comes with vertical scaling enabled by default, in addition to offering advanced storage auto-scaling capabilities, ensuring that the cluster dynamically adjusts to the data volume and workload.
To complement the robustness of the configuration, the module allows the inclusion of analytical nodes and read-only nodes, expanding the possibilities of using the cluster for scenarios that require in-depth analysis or intensive read operations without impacting overall performance.
The default configuration includes smart preset values, such as the MongoDB version, which is set to "7.0" to take advantage of the latest features while maintaining the option to adjust to specific versions as needed. This “best practices” approach ensures a solid starting point for most projects, reducing the need for manual adjustments and simplifying the deployment process.
Additionally, the ability to deploy clusters in any region and cloud provider — such as AWS, Azure, or GCP — offers unmatched flexibility, allowing teams to choose the best solution based on their cost, performance, and compliance preferences.
In summary, this module not only facilitates the configuration and management of MongoDB Atlas clusters with an extensive range of options and adjustments but also promotes secure and efficient configuration practices, making it a valuable tool for developers and database administrators in implementing scalable and reliable data solutions in the cloud.
The use of the lifecycle directive with the
ignore_changes option in the Terraform code was specifically implemented to accommodate manual upscale situations of the MongoDB Atlas cluster, which should not be automatically reversed by Terraform in subsequent executions. This approach ensures that, after a manual increase in storage capacity (disk_size_gb) or other specific replication configurations (replication_specs), Terraform does not attempt to undo these changes to align the resource state with the original definition in the code. Essentially, it allows configuration adjustments made outside of Terraform, such as an upscale to optimize performance or meet growing demands, to remain intact without being overwritten by future Terraform executions, ensuring operational flexibility while maintaining infrastructure management as code.In the variable.tf file, we create variables with default values:
1 variable "name" { 2 description = "The name of the cluster." 3 type = string 4 } 5 6 variable "cluster_type" { 7 description = <<HEREDOC 8 Optional - Specifies the type of the cluster that you want to modify. You cannot convert 9 a sharded cluster deployment to a replica set deployment. Accepted values include: 10 REPLICASET for Replica set, SHARDED for Sharded cluster, and GEOSHARDED for Global Cluster 11 HEREDOC 12 default = "REPLICASET" 13 } 14 15 16 variable "mongo_db_major_version" { 17 description = <<HEREDOC 18 Optional - Version of the cluster to deploy. Atlas supports the following MongoDB versions 19 for M10+ clusters: 5.0, 6.0 or 7.0. 20 HEREDOC 21 default = "7.0" 22 } 23 24 variable "version_release_system" { 25 description = <<HEREDOC 26 Optional - Release cadence that Atlas uses for this cluster. This parameter defaults to LTS. 27 If you set this field to CONTINUOUS, you must omit the mongo_db_major_version field. Atlas accepts: 28 CONTINUOUS - Atlas deploys the latest version of MongoDB available for the cluster tier. 29 LTS - Atlas deploys the latest Long Term Support (LTS) version of MongoDB available for the cluster tier. 30 HEREDOC 31 default = "LTS" 32 } 33 34 35 36 variable "disk_size_gb" { 37 description = <<HEREDOC 38 Optional - Capacity, in gigabytes, of the host’s root volume. Increase this 39 number to add capacity, up to a maximum possible value of 4096 (i.e., 4 TB). This value must 40 be a positive integer. If you specify diskSizeGB with a lower disk size, Atlas defaults to 41 the minimum disk size value. Note: The maximum value for disk storage cannot exceed 50 times 42 the maximum RAM for the selected cluster. If you require additional storage space beyond this 43 limitation, consider upgrading your cluster to a higher tier. 44 HEREDOC 45 type = number 46 default = 10 47 } 48 49 variable "backup_enabled" { 50 description = <<HEREDOC 51 Optional - Flag indicating if the cluster uses Cloud Backup for backups. If true, the cluster 52 uses Cloud Backup for backups. The default is true. 53 HEREDOC 54 type = bool 55 default = true 56 } 57 58 variable "pit_enabled" { 59 description = <<HEREDOC 60 Optional - Flag that indicates if the cluster uses Continuous Cloud Backup. If set to true, 61 backup_enabled must also be set to true. The default is true. 62 HEREDOC 63 type = bool 64 default = true 65 } 66 67 variable "disk_gb_enabled" { 68 description = <<HEREDOC 69 Optional - Specifies whether disk auto-scaling is enabled. The default is true. 70 HEREDOC 71 type = bool 72 default = true 73 } 74 75 variable "region_configs" { 76 description = <<HEREDOC 77 Required - Physical location of the region. Each regionsConfig document describes 78 the region’s priority in elections and the number and type of MongoDB nodes Atlas 79 deploys to the region. You can be set that parameters: 80 81 - region_name - Optional - Physical location of your MongoDB cluster. The region you choose can affect network latency for clients accessing your databases. 82 83 - electable_nodes - Optional - Number of electable nodes for Atlas to deploy to the region. Electable nodes can become the primary and can facilitate local reads. The total number of electableNodes across all replication spec regions must total 3, 5, or 7. Specify 0 if you do not want any electable nodes in the region. You cannot create electable nodes in a region if priority is 0. 84 85 - priority - Optional - Election priority of the region. For regions with only read-only nodes, set this value to 0. For regions where electable_nodes is at least 1, each region must have a priority of exactly one (1) less than the previous region. The first region 86 must have a priority of 7. The lowest possible priority is 1. The priority 7 region identifies the Preferred Region of the cluster. Atlas places the primary node in the Preferred Region. Priorities 1 through 7 are exclusive - no more than one region per cluster can be assigned a given priority. Example: If you have three regions, their priorities would be 7, 6, and 5 respectively. If you added two more regions for supporting electable nodes, the priorities of those regions would be 4 and 3 respectively. 87 88 - read_only_nodes - Optional - Number of read-only nodes for Atlas to deploy to the region. 89 Read-only nodes can never become the primary, but can facilitate local-reads. Specify 0 if you do not want any read-only nodes in the region. 90 91 - analytics_nodes - Optional - The number of analytics nodes for Atlas to deploy to the region. 92 Analytics nodes are useful for handling analytic data such as reporting queries from BI Connector for Atlas. Analytics nodes are read-only, and can never become the primary. If you do not specify this option, no analytics nodes are deployed to the region. 93 HEREDOC 94 type = any 95 } 96 97 # ------------------------------------------------------------------------------ 98 # MONGODB BI CONNECTOR 99 # ------------------------------------------------------------------------------ 100 101 variable "bi_connector_enabled" { 102 description = <<HEREDOC 103 Optional - Specifies whether or not BI Connector for Atlas is enabled on the cluster. 104 Set to true to enable BI Connector for Atlas. Set to false to disable BI Connector for Atlas. 105 HEREDOC 106 type = bool 107 default = false 108 } 109 110 variable "bi_connector_read_preference" { 111 description = <<HEREDOC 112 Optional - Specifies the read preference to be used by BI Connector for Atlas on the cluster. 113 Each BI Connector for Atlas read preference contains a distinct combination of readPreference and readPreferenceTags options. For details on BI Connector for Atlas read preferences, refer to the BI Connector Read Preferences Table. 114 Set to "primary" to have BI Connector for Atlas read from the primary. Set to "secondary" to have BI Connector for Atlas read from a secondary member. Default if there are no analytics nodes in the cluster. Set to "analytics" to have BI Connector for Atlas read from an analytics node. Default if the cluster contains analytics nodes. 115 HEREDOC 116 type = string 117 default = "secondary" 118 } 119 120 # ------------------------------------------------------------------------------ 121 # MONGODB ADVANCED CONFIGURATION 122 # ------------------------------------------------------------------------------ 123 variable "fail_index_key_too_long" { 124 description = <<HEREDOC 125 Optional - When true, documents can only be updated or inserted if, for all indexed fields on the target collection, the corresponding index entries do not exceed 1024 bytes. When false, mongod writes documents that exceed the limit but does not index them. 126 HEREDOC 127 type = bool 128 default = false 129 } 130 131 variable "javascript_enabled" { 132 description = <<HEREDOC 133 Optional - When true, the cluster allows execution of operations that perform server-side executions of JavaScript. When false, the cluster disables execution of those operations. 134 HEREDOC 135 type = bool 136 default = true 137 } 138 139 variable "minimum_enabled_tls_protocol" { 140 description = <<HEREDOC 141 Optional - Sets the minimum Transport Layer Security (TLS) version the cluster accepts for incoming connections. Valid values are: TLS1_0, TLS1_1, TLS1_2. The default is "TLS1_2". 142 HEREDOC 143 default = "TLS1_2" 144 } 145 146 variable "no_table_scan" { 147 description = <<HEREDOC 148 Optional - When true, the cluster disables the execution of any query that requires a collection scan to return results. When false, the cluster allows the execution of those operations. 149 HEREDOC 150 type = bool 151 default = false 152 } 153 154 variable "oplog_size_mb" { 155 description = <<HEREDOC 156 Optional - The custom oplog size of the cluster. 157 Without a value that indicates that the cluster uses the default oplog size calculated by Atlas. 158 HEREDOC 159 type = number 160 default = null 161 } 162 163 variable "default_read_concern" { 164 description = <<HEREDOC 165 Optional - The default read concern for the cluster. The default is "local". 166 HEREDOC 167 default = "local" 168 } 169 170 variable "default_write_concern" { 171 description = <<HEREDOC 172 Optional - The default write concern for the cluster. The default is "majority". 173 HEREDOC 174 default = "majority" 175 } 176 177 variable "oplog_min_retention_hours" { 178 description = <<HEREDOC 179 Minimum retention window for cluster's oplog expressed in hours. 180 A value of null indicates that the cluster uses the default minimum oplog window that MongoDB Cloud calculates. 181 HEREDOC 182 type = number 183 default = null 184 } 185 186 variable "transaction_lifetime_limit_seconds" { 187 description = <<HEREDOC 188 Optional - Lifetime, in seconds, of multi-document transactions. Defaults to 60 seconds. 189 HEREDOC 190 type = number 191 default = 60 192 } 193 194 variable "sample_size_bi_connector" { 195 description = <<HEREDOC 196 Optional - Number of documents per database to sample when gathering schema information. Defaults to 100. 197 Available only for Atlas deployments in which BI Connector for Atlas is enabled. 198 HEREDOC 199 type = number 200 default = 100 201 } 202 203 variable "sample_refresh_interval_bi_connector" { 204 description = <<HEREDOC 205 Optional - Interval in seconds at which the mongosqld process re-samples data to create its relational schema. The default value is 300. 206 The specified value must be a positive integer. 207 Available only for Atlas deployments in which BI Connector for Atlas is enabled. 208 HEREDOC 209 type = number 210 default = 300 211 } 212 213 # ------------------------------------------------------------------------------ 214 # MONGODB REPLICATION SPECS 215 # ------------------------------------------------------------------------------ 216 variable "num_shards" { 217 description = <<HEREDOC 218 Optional - Number of shards, minimum 1. 219 The default is null if type is REPLICASET. 220 HEREDOC 221 type = number 222 default = null 223 } 224 225 # ------------------------------------------------------------------------------ 226 # MONGODB BACKUP POLICY 227 # ------------------------------------------------------------------------------ 228 variable "update_snapshots" { 229 description = <<HEREDOC 230 Optional - Specify true to apply the retention changes in the updated backup policy to snapshots that Atlas took previously. 231 HEREDOC 232 type = bool 233 default = false 234 } 235 236 variable "reference_hour_of_day" { 237 description = <<HEREDOC 238 Optional - Hour of the day in UTC at which Atlas takes the daily snapshots of the cluster. 239 HEREDOC 240 type = number 241 default = 3 242 } 243 244 variable "reference_minute_of_hour" { 245 description = <<HEREDOC 246 Optional - Minute of the hour in UTC at which Atlas takes the daily snapshots of the cluster. 247 HEREDOC 248 type = number 249 default = 30 250 } 251 252 variable "restore_window_days" { 253 description = <<HEREDOC 254 Optional - Number of days Atlas retains the backup snapshots in the snapshot schedule. 255 HEREDOC 256 type = number 257 default = 3 258 } 259 260 variable "policy_item_hourly_frequency_interval" { 261 description = <<HEREDOC 262 Optional - Interval, in hours, between snapshots that Atlas takes of the cluster. 263 HEREDOC 264 type = number 265 default = 12 266 } 267 268 variable "policy_item_hourly_retention_unit" { 269 description = <<HEREDOC 270 Optional - Unit of time that Atlas retains each snapshot in the hourly snapshot schedule. 271 HEREDOC 272 type = string 273 default = "days" 274 } 275 276 variable "policy_item_hourly_retention_value" { 277 description = <<HEREDOC 278 Optional - Number of units of time that Atlas retains each snapshot in the hourly snapshot schedule. 279 HEREDOC 280 type = number 281 default = 3 282 } 283 284 variable "policy_item_daily_frequency_interval" { 285 description = <<HEREDOC 286 Optional - Interval, in days, between snapshots that Atlas takes of the cluster. 287 HEREDOC 288 type = number 289 default = 1 290 } 291 292 variable "policy_item_daily_retention_unit" { 293 description = <<HEREDOC 294 Optional - Unit of time that Atlas retains each snapshot in the daily snapshot schedule. 295 HEREDOC 296 type = string 297 default = "days" 298 } 299 300 variable "policy_item_daily_retention_value" { 301 description = <<HEREDOC 302 Optional - Number of units of time that Atlas retains each snapshot in the daily snapshot schedule. 303 HEREDOC 304 type = number 305 default = 7 306 } 307 308 variable "policy_item_weekly_frequency_interval" { 309 description = <<HEREDOC 310 Optional - Interval, in weeks, between snapshots that Atlas takes of the cluster. 311 HEREDOC 312 type = number 313 default = 1 314 } 315 316 variable "policy_item_weekly_retention_unit" { 317 description = <<HEREDOC 318 Optional - Unit of time that Atlas retains each snapshot in the weekly snapshot schedule. 319 HEREDOC 320 type = string 321 default = "weeks" 322 } 323 324 variable "policy_item_weekly_retention_value" { 325 description = <<HEREDOC 326 Optional - Number of units of time that Atlas retains each snapshot in the weekly snapshot schedule. 327 HEREDOC 328 type = number 329 default = 4 330 } 331 332 333 variable "policy_item_monthly_frequency_interval" { 334 description = <<HEREDOC 335 Optional - Interval, in months, between snapshots that Atlas takes of the cluster. 336 HEREDOC 337 type = number 338 default = 1 339 } 340 341 variable "policy_item_monthly_retention_unit" { 342 description = <<HEREDOC 343 Optional - Unit of time that Atlas retains each snapshot in the monthly snapshot schedule. 344 HEREDOC 345 type = string 346 default = "months" 347 } 348 349 350 variable "policy_item_monthly_retention_value" { 351 description = <<HEREDOC 352 Optional - Number of units of time that Atlas retains each snapshot in the monthly snapshot schedule. 353 HEREDOC 354 type = number 355 default = 12 356 } 357 358 # ------------------------------------------------------------------------------ 359 # MONGODB TAGS 360 # ------------------------------------------------------------------------------ 361 variable "application" { 362 description = <<HEREDOC 363 Optional - Key-value pairs that tag and categorize the cluster for billing and organizational purposes. 364 HEREDOC 365 type = string 366 } 367 368 variable "environment" { 369 description = <<HEREDOC 370 Optional - Key-value pairs that tag and categorize the cluster for billing and organizational purposes. 371 HEREDOC 372 type = string 373 } 374 375 # ------------------------------------------------------------------------------ 376 # MONGODB DATA 377 # ------------------------------------------------------------------------------ 378 variable "project_name" { 379 description = <<HEREDOC 380 Required - The name of the Atlas project in which to create the cluster. 381 HEREDOC 382 type = string 383 }
We configured a file called locals.tf specifically to define two exemplary tags, aiming to identify the name of our application and the environment in which it operates. If you prefer, it is possible to adopt an external tag module, similar to those used in AWS, and integrate it into this configuration.
1 locals { 2 tags = { 3 name = var.application 4 environment = var.environment 5 } 6 }
In this article, we embrace the use of data sources in Terraform to establish a dynamic connection with existing resources, such as our MongoDB Atlas project. Specifically, in the data.tf file, we define a
mongodbatlas_project data source to access information about an existing project based on its name:1 data "mongodbatlas_project" "default" { 2 name = var.project_name 3 }
Here,
var.project_name refers to the name of the project we want to query, an approach that allows us to keep our configuration flexible and reusable. The value of this variable can be provided in several ways, significantly expanding the possibilities for using our infrastructure as code.The terraform.tfvars file is used to define variable values that will be applied in the Terraform configuration, making infrastructure as code more dynamic and adaptable to the specific needs of each project or environment. In your case, the terraform.tfvars file contains essential values for creating a cluster in MongoDB Atlas, including details such as the project name, cluster characteristics, and auto-scaling settings. See below how these definitions apply:
1 project_name = "project-test" 2 name = "cluster-demo" 3 cluster_type = "REPLICASET" 4 application = "teste-cluster" 5 environment = "dev" 6 7 region_configs = [{ 8 provider_name = "AWS" 9 region_name = "US_EAST_1" 10 priority = 7 11 12 electable_specs = { 13 instance_size = "M10" 14 node_count = 3 15 disk_iops = 120 16 disk_size_gb = 10 17 ebs_volume_type = "STANDARD" 18 } 19 20 auto_scaling = { 21 disk_gb_enabled = true 22 compute_enabled = true 23 compute_scale_down_enabled = true 24 compute_min_instance_size = "M10" 25 compute_max_instance_size = "M30" 26 } 27 }]
These values defined in terraform.tfvars are used by Terraform to populate corresponding variables in your configuration. For example, if you have a module or feature that creates a cluster in MongoDB Atlas, you can reference these variables directly to configure properties such as the project name, cluster settings, and regional specifications. This allows significant flexibility in customizing your infrastructure based on different environments or project requirements.
The file structure was as follows:
- main.tf: In this file, we will define the main resource, the mongodbatlas_advanced_cluster, and mongodbatlas_cloud_backup_schedule. Here, you have configured the cluster and backup routines.
- provider.tf: This file is where we define the provider we are using — in our case, mongodbatlas. We will specify using environment variables, as mentioned previously.
- terraform.tfvars: This file contains the variables that will be used in our cluster. For example, the cluster name, cluster information, version, size, among others.
- variable.tf: Here, we define the variables mentioned in the terraform.tfvars file, specifying the type and optionally a default value.
- version.tf: This file is used to specify the version of Terraform and the providers we are using.
- data.tf: Here, we specify a data source that will bring us information about our created project. We will search for its name and for our module, it will give us the project ID.
- locals.tf: We specify example tags to use in our cluster.
Now is the time to apply. =D
We run a
terraform init in the terminal in the folder where the files are located so that it downloads the providers, modules, etc…Note: Remember to export the environment variables with the public and private keys.
1 export MONGODB_ATLAS_PUBLIC_KEY="public" 2 export MONGODB_ATLAS_PRIVATE_KEY="private"
Now, we run
terraform init.1 (base) samuelmolling@Samuels-MacBook-Pro cluster % terraform init 2 3 Initializing the backend... 4 5 Initializing provider plugins... 6 - Finding mongodb/mongodbatlas versions matching "1.14.0"... 7 - Installing mongodb/mongodbatlas v1.14.0... 8 - Installed mongodb/mongodbatlas v1.14.0 (signed by a HashiCorp partner, key ID 2A32ED1F3AD25ABF) 9 10 Partner and community providers are signed by their developers. 11 If you'd like to know more about provider signing, you can read about it here: 12 https://www.terraform.io/docs/cli/plugins/signing.html 13 14 Terraform has created a lock file .terraform.lock.hcl to record the provider selections it made above. Include this file in your version control repository so that Terraform can guarantee to make the same selections by default when you run `terraform init` in the future. 15 16 Terraform has been successfully initialized! 17 18 You may now begin working with Terraform. Try running `terraform plan` to see any changes that are required for your infrastructure. All Terraform commands should now work. 19 20 If you ever set or change modules or backend configuration for Terraform, rerun this command to reinitialize your working directory. If you forget, other commands will detect it and remind you to do so if necessary.
Now that init has worked, let's run
terraform plan and evaluate what will happen:1 (base) samuelmolling@Samuels-MacBook-Pro cluster % terraform plan 2 data.mongodbatlas_project.default: Reading... 3 data.mongodbatlas_project.default: Read complete after 2s [id=65bfd71a08b61c36ca4d8eaa] 4 5 Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols: 6 + create 7 8 Terraform will perform the following actions: 9 10 # mongodbatlas_advanced_cluster.default will be created 11 + resource "mongodbatlas_advanced_cluster" "default" { 12 + advanced_configuration = [ 13 + { 14 + default_read_concern = "local" 15 + default_write_concern = "majority" 16 + fail_index_key_too_long = false 17 + javascript_enabled = true 18 + minimum_enabled_tls_protocol = "TLS1_2" 19 + no_table_scan = false 20 + oplog_size_mb = (known after apply) 21 + sample_refresh_interval_bi_connector = 300 22 + sample_size_bi_connector = 100 23 + transaction_lifetime_limit_seconds = 60 24 }, 25 ] 26 + backup_enabled = true 27 + cluster_id = (known after apply) 28 + cluster_type = "REPLICASET" 29 + connection_strings = (known after apply) 30 + create_date = (known after apply) 31 + disk_size_gb = 10 32 + encryption_at_rest_provider = (known after apply) 33 + id = (known after apply) 34 + mongo_db_major_version = "7.0" 35 + mongo_db_version = (known after apply) 36 + name = "cluster-demo" 37 + paused = (known after apply) 38 + pit_enabled = true 39 + project_id = "65bfd71a08b61c36ca4d8eaa" 40 + root_cert_type = (known after apply) 41 + state_name = (known after apply) 42 + termination_protection_enabled = (known after apply) 43 + version_release_system = (known after apply) 44 45 + bi_connector_config { 46 + enabled = false 47 + read_preference = "secondary" 48 } 49 50 + replication_specs { 51 + container_id = (known after apply) 52 + id = (known after apply) 53 + num_shards = 1 54 + zone_name = "ZoneName managed by Terraform" 55 56 + region_configs { 57 + priority = 7 58 + provider_name = "AWS" 59 + region_name = "US_EAST_1" 60 61 + analytics_auto_scaling { 62 + compute_enabled = (known after apply) 63 + compute_max_instance_size = (known after apply) 64 + compute_min_instance_size = (known after apply) 65 + compute_scale_down_enabled = (known after apply) 66 + disk_gb_enabled = (known after apply) 67 } 68 69 + analytics_specs { 70 + disk_iops = (known after apply) 71 + ebs_volume_type = "STANDARD" 72 + instance_size = "M10" 73 + node_count = 0 74 } 75 76 + auto_scaling { 77 + compute_enabled = true 78 + compute_max_instance_size = "M30" 79 + compute_min_instance_size = "M10" 80 + compute_scale_down_enabled = true 81 + disk_gb_enabled = true 82 } 83 84 + electable_specs { 85 + disk_iops = (known after apply) 86 + ebs_volume_type = "STANDARD" 87 + instance_size = "M10" 88 + node_count = 3 89 } 90 91 + read_only_specs { 92 + disk_iops = (known after apply) 93 + ebs_volume_type = "STANDARD" 94 + instance_size = "M10" 95 + node_count = 0 96 } 97 } 98 } 99 100 + tags { 101 + key = "environment" 102 + value = "dev" 103 } 104 + tags { 105 + key = "name" 106 + value = "teste-cluster" 107 } 108 } 109 110 # mongodbatlas_cloud_backup_schedule.default will be created 111 + resource "mongodbatlas_cloud_backup_schedule" "default" { 112 + auto_export_enabled = (known after apply) 113 + cluster_id = (known after apply) 114 + cluster_name = "cluster-demo" 115 + id = (known after apply) 116 + id_policy = (known after apply) 117 + next_snapshot = (known after apply) 118 + project_id = "65bfd71a08b61c36ca4d8eaa" 119 + reference_hour_of_day = 3 120 + reference_minute_of_hour = 30 121 + restore_window_days = 3 122 + update_snapshots = false 123 + use_org_and_group_names_in_export_prefix = (known after apply) 124 125 + policy_item_daily { 126 + frequency_interval = 1 127 + frequency_type = (known after apply) 128 + id = (known after apply) 129 + retention_unit = "days" 130 + retention_value = 7 131 } 132 133 + policy_item_hourly { 134 + frequency_interval = 12 135 + frequency_type = (known after apply) 136 + id = (known after apply) 137 + retention_unit = "days" 138 + retention_value = 3 139 } 140 141 + policy_item_monthly { 142 + frequency_interval = 1 143 + frequency_type = (known after apply) 144 + id = (known after apply) 145 + retention_unit = "months" 146 + retention_value = 12 147 } 148 149 + policy_item_weekly { 150 + frequency_interval = 1 151 + frequency_type = (known after apply) 152 + id = (known after apply) 153 + retention_unit = "weeks" 154 + retention_value = 4 155 } 156 } 157 158 Plan: 2 to add, 0 to change, 0 to destroy. 159 160 ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── 161 162 Note: You didn't use the -out option to save this plan, so Terraform can't guarantee to take exactly these actions if you run `terraform apply` now.
Show! It was exactly the output we expected to see, the creation of a cluster resource with the backup policies. Let's apply this!
When running the
terraform apply command, you will be prompted for approval with yes or no. Type yes.1 (base) samuelmolling@Samuels-MacBook-Pro cluster % terraform apply 2 3 data.mongodbatlas_project.default: Reading... 4 5 data.mongodbatlas_project.default: Read complete after 2s [id=65bfd71a08b61c36ca4d8eaa] 6 7 Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols: 8 + create 9 10 Terraform will perform the following actions: 11 12 # mongodbatlas_advanced_cluster.default will be created 13 + resource "mongodbatlas_advanced_cluster" "default" { 14 + advanced_configuration = [ 15 + { 16 + default_read_concern = "local" 17 + default_write_concern = "majority" 18 + fail_index_key_too_long = false 19 + javascript_enabled = true 20 + minimum_enabled_tls_protocol = "TLS1_2" 21 + no_table_scan = false 22 + oplog_size_mb = (known after apply) 23 + sample_refresh_interval_bi_connector = 300 24 + sample_size_bi_connector = 100 25 + transaction_lifetime_limit_seconds = 60 26 }, 27 ] 28 + backup_enabled = true 29 + cluster_id = (known after apply) 30 + cluster_type = "REPLICASET" 31 + connection_strings = (known after apply) 32 + create_date = (known after apply) 33 + disk_size_gb = 10 34 + encryption_at_rest_provider = (known after apply) 35 + id = (known after apply) 36 + mongo_db_major_version = "7.0" 37 + mongo_db_version = (known after apply) 38 + name = "cluster-demo" 39 + paused = (known after apply) 40 + pit_enabled = true 41 + project_id = "65bfd71a08b61c36ca4d8eaa" 42 + root_cert_type = (known after apply) 43 + state_name = (known after apply) 44 + termination_protection_enabled = (known after apply) 45 + version_release_system = (known after apply) 46 + bi_connector_config { 47 + enabled = false 48 + read_preference = "secondary" 49 } 50 51 + replication_specs { 52 + container_id = (known after apply) 53 + id = (known after apply) 54 + num_shards = 1 55 + zone_name = "ZoneName managed by Terraform" 56 57 + region_configs { 58 + priority = 7 59 + provider_name = "AWS" 60 + region_name = "US_EAST_1" 61 62 + analytics_auto_scaling { 63 + compute_enabled = (known after apply) 64 + compute_max_instance_size = (known after apply) 65 + compute_min_instance_size = (known after apply) 66 + compute_scale_down_enabled = (known after apply) 67 + disk_gb_enabled = (known after apply) 68 } 69 70 + analytics_specs { 71 + disk_iops = (known after apply) 72 + ebs_volume_type = "STANDARD" 73 + instance_size = "M10" 74 + node_count = 0 75 } 76 77 + auto_scaling { 78 + compute_enabled = true 79 + compute_max_instance_size = "M30" 80 + compute_min_instance_size = "M10" 81 + compute_scale_down_enabled = true 82 + disk_gb_enabled = true 83 } 84 85 + electable_specs { 86 + disk_iops = (known after apply) 87 + ebs_volume_type = "STANDARD" 88 + instance_size = "M10" 89 + node_count = 3 90 } 91 92 + read_only_specs { 93 + disk_iops = (known after apply) 94 + ebs_volume_type = "STANDARD" 95 + instance_size = "M10" 96 + node_count = 0 97 } 98 } 99 } 100 101 + tags { 102 + key = "environment" 103 + value = "dev" 104 } 105 + tags { 106 + key = "name" 107 + value = "teste-cluster" 108 } 109 } 110 111 # mongodbatlas_cloud_backup_schedule.default will be created 112 + resource "mongodbatlas_cloud_backup_schedule" "default" { 113 + auto_export_enabled = (known after apply) 114 + cluster_id = (known after apply) 115 + cluster_name = "cluster-demo" 116 + id = (known after apply) 117 + id_policy = (known after apply) 118 + next_snapshot = (known after apply) 119 + project_id = "65bfd71a08b61c36ca4d8eaa" 120 + reference_hour_of_day = 3 121 + reference_minute_of_hour = 30 122 + restore_window_days = 3 123 + update_snapshots = false 124 + use_org_and_group_names_in_export_prefix = (known after apply) 125 + policy_item_daily { 126 + frequency_interval = 1 127 + frequency_type = (known after apply) 128 + id = (known after apply) 129 + retention_unit = "days" 130 + retention_value = 7 131 } 132 133 + policy_item_hourly { 134 + frequency_interval = 12 135 + frequency_type = (known after apply) 136 + id = (known after apply) 137 + retention_unit = "days" 138 + retention_value = 3 139 } 140 141 + policy_item_monthly { 142 + frequency_interval = 1 143 + frequency_type = (known after apply) 144 + id = (known after apply) 145 + retention_unit = "months" 146 + retention_value = 12 147 } 148 149 + policy_item_weekly { 150 + frequency_interval = 1 151 + frequency_type = (known after apply) 152 + id = (known after apply) 153 + retention_unit = "weeks" 154 + retention_value = 4 155 } 156 } 157 158 Plan: 2 to add, 0 to change, 0 to destroy. 159 160 Do you want to perform these actions? 161 Terraform will perform the actions described above. 162 Only 'yes' will be accepted to approve. 163 164 Enter a value: yes 165 166 mongodbatlas_advanced_cluster.default: Creating... 167 mongodbatlas_advanced_cluster.default: Still creating... [10s elapsed] 168 mongodbatlas_advanced_cluster.default: Still creating... [8m40s elapsed] 169 mongodbatlas_advanced_cluster.default: Creation complete after 8m46s [id=Y2x1c3Rlcl9pZA==:NjViZmRmYzczMTBiN2Y2ZDFhYmIxMmQ0-Y2x1c3Rlcl9uYW1l:Y2x1c3Rlci1kZW1v-cHJvamVjdF9pZA==:NjViZmQ3MWEwOGI2MWMzNmNhNGQ4ZWFh] 170 mongodbatlas_cloud_backup_schedule.default: Creating... 171 mongodbatlas_cloud_backup_schedule.default: Creation complete after 2s [id=Y2x1c3Rlcl9uYW1l:Y2x1c3Rlci1kZW1v-cHJvamVjdF9pZA==:NjViZmQ3MWEwOGI2MWMzNmNhNGQ4ZWFh] 172 173 Apply complete! Resources: 2 added, 0 changed, 0 destroyed.
This process took eight minutes and 40 seconds to execute. I shortened the log output, but don't worry if this step takes time.
Now, let’s look in Atlas to see if the cluster was created successfully…
We were able to create our first replica set with a standard backup policy with PITR and scheduled snapshots.
In this tutorial, we saw how to create the first cluster in our project created in the last article. We created a module that also includes a backup policy. In an upcoming article, we will look at how to create an API key and user using Terraform and Atlas.
To learn more about MongoDB and various tools, I invite you to visit the Developer Center to read the other articles.
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