AKS variant

This folder contains the variant to use when deploying in Microsoft Azure using an AKS cluster.

Usage

This module can be declared by adding the following block on your Terraform configuration:

module "thanos" {
  source = "git::https://github.com/camptocamp/devops-stack-module-thanos.git//aks?ref=<RELEASE>"

  cluster_name     = TODO
  base_domain      = TODO
  cluster_issuer   = local.cluster_issuer
  argocd_namespace = module.argocd_bootstrap.argocd_namespace

  metrics_storage = {
    container           = azurerm_storage_container.thanos.name
    storage_account     = azurerm_storage_account.thanos.name
    storage_account_key = azurerm_storage_account.thanos.primary_access_key
  }

  thanos = {
    oidc = module.oidc.oidc
  }

  dependency_ids = {
    argocd       = module.argocd_bootstrap.id
    traefik      = module.traefik.id
    cert-manager = module.cert-manager.id
  }
}

As you can see, a minimum requirement for this module is an Azure Blob Storage bucket and an OIDC provider (more information below).

You are in charge of creating an Azure Blob Storage for Thanos to store the archived metrics. We’ve decided to keep the creation of this bucket outside of this module, mainly because the persistence of the data should not be related to the instantiation of the module itself.
Check the AKS deployment example to see how to create the storage and to better understand the values passed on the example above.
Do not forget that the bucket configuration also needs to be passed to the module kube-prometheus-stack.

Although the declaration above allows you to have a barebones Thanos deployed, it is highly recommended that you customize a few settings for a production-ready deployment. You need to at least configure the resource requirements for a few of the Thanos' components and the size of the persistent volume used by the compactor. You can also configure the compactor retention times, as in the example below.

module "thanos" {
  source = "git::https://github.com/camptocamp/devops-stack-module-thanos.git//aks?ref=<RELEASE>"

  cluster_name     = TODO
  base_domain      = TODO
  cluster_issuer   = local.cluster_issuer
  argocd_namespace = module.argocd_bootstrap.argocd_namespace

  metrics_storage = {
    container           = azurerm_storage_container.thanos.name
    storage_account     = azurerm_storage_account.thanos.name
    storage_account_key = azurerm_storage_account.thanos.primary_access_key
  }

  thanos = {
    # OIDC configuration
    oidc = module.oidc.oidc

    # Configuration of the persistent volume for the compactor
    compactor_persistent_size = "100Gi"

    # Resources configuration for the pods
    compactor_resources = {
      limits = {
        memory = "1Gi"
      }
      requests = {
        cpu    = "0.5"
        memory = "512Mi"
      }
    }
    storegateway_resources = {
      limits = {
        memory = "1Gi"
      }
      requests = {
        cpu    = "0.5"
        memory = "1Gi"
      }
    }
    query_resources = {
      limits = {
        memory = "1Gi"
      }
      requests = {
        cpu    = "0.5"
        memory = "512Mi"
      }
    }

    # Retention settings for the compactor
    compactor_retention = {
      raw      = "60d"
      five_min = "120d"
      one_hour = "240d"
    }
  }

  depends_on = [module.argocd_bootstrap]
}

As you can see on the examples above, the variable thanos provides an interface to customize the most frequently used settings. This variable is merged with the local value thanos_defaults, which contains some sensible defaults to have a barebones working deployment. You can check the default values on the local.tf file.

If there is a need to configure something besides the common settings that we have provided above, you can customize the chart’s values.yaml by adding an Helm configuration as an HCL structure:

module "thanos" {
  source = "git::https://github.com/camptocamp/devops-stack-module-thanos.git//aks?ref=<RELEASE>"

  cluster_name     = TODO
  base_domain      = TODO
  cluster_issuer   = local.cluster_issuer
  argocd_namespace = module.argocd_bootstrap.argocd_namespace

  metrics_storage = {
    container           = azurerm_storage_container.thanos.name
    storage_account     = azurerm_storage_account.thanos.name
    storage_account_key = azurerm_storage_account.thanos.primary_access_key
  }

  thanos = {
    oidc = module.oidc.oidc
  }

  helm_values = [{ # Note the curly brackets here
    thanos = {
      map = {
        string = "string"
        bool   = true
      }
      sequence = [
        {
          key1 = "value1"
          key2 = "value2"
        },
        {
          key1 = "value1"
          key2 = "value2"
        },
      ]
      sequence2 = [
        "string1",
        "string2"
      ]
    }
  }]

  depends_on = [module.argocd_bootstrap]
}

OIDC

This module was developed with OIDC in mind.

There is an OIDC proxy container deployed as a sidecar on each pod that has a web interface. Consequently, the thanos variable is expected to have a map oidc containing at least the Issuer URL, the Client ID, and the Client Secret.

You can pass these values by pointing an output from another module (as above), or by defining them explicitly:

module "thanos" {
  ...
  thanos = {
    oidc = {
      issuer_url    = "<URL>"
      client_id     = "<ID>"
      client_secret = "<SECRET>"
    }
  }
  ...
}

Resource Configuration

Since the resource requirements are not the same on every deployment and because the consumed resources also influence the cost associated, we refrained from configuring default resource requirements for the components of Thanos. We did, however, set memory limits for some of the pods (query, storegateway and compactor all have a 1 GB memory limit). We recommend that you customize these values as you see fit.

At the very least you should configure the size for the PersistentVolume used by the compactor.

This value MUST be configured otherwise the compactor will NOT work on a production deployment. The Thanos documentation recommends a size of 100-300 GB.

Technical Reference

Dependencies

module.argocd_bootstrap.id

Obviously, the module depends on an already running Argo CD in the cluster in order for the application to be created.

module.traefik.id and module.cert-manager.id

This module has multiple ingresses and consequently it must be deployed after the module traefik and cert-manager.

Requirements

The following requirements are needed by this module:

Providers

The following providers are used by this module:

Modules

The following Modules are called:

thanos

Source: ../

Version:

Resources

The following resources are used by this module:

Required Inputs

The following input variables are required:

metrics_storage

Description: Azure Blob Storage configuration for metric archival.

Type:

object({
    container                        = string
    storage_account                  = string
    managed_identity_node_rg_name    = optional(string, null)
    managed_identity_oidc_issuer_url = optional(string, null)
    storage_account_key              = optional(string, null)
  })

cluster_name

Description: Name given to the cluster. Value used for the ingress' URL of the application.

Type: string

base_domain

Description: Base domain of the cluster. Value used for the ingress' URL of the application.

Type: string

Optional Inputs

The following input variables are optional (have default values):

argocd_project

Description: Name of the Argo CD AppProject where the Application should be created. If not set, the Application will be created in a new AppProject only for this Application.

Type: string

Default: null

argocd_labels

Description: Labels to attach to the Argo CD Application resource.

Type: map(string)

Default: {}

destination_cluster

Description: Destination cluster where the application should be deployed.

Type: string

Default: "in-cluster"

target_revision

Description: Override of target revision of the application chart.

Type: string

Default: "v2.7.0"

cluster_issuer

Description: SSL certificate issuer to use. Usually you would configure this value as letsencrypt-staging or letsencrypt-prod on your root *.tf files.

Type: string

Default: "selfsigned-issuer"

helm_values

Description: Helm chart value overrides. They should be passed as a list of HCL structures.

Type: any

Default: []

deep_merge_append_list

Description: A boolean flag to enable/disable appending lists instead of overwriting them.

Type: bool

Default: false

app_autosync

Description: Automated sync options for the Argo CD Application resource.

Type:

object({
    allow_empty = optional(bool)
    prune       = optional(bool)
    self_heal   = optional(bool)
  })

Default:

{
  "allow_empty": false,
  "prune": true,
  "self_heal": true
}

dependency_ids

Description: IDs of the other modules on which this module depends on.

Type: map(string)

Default: {}

thanos

Description: Most frequently used Thanos settings. This variable is merged with the local value thanos_defaults, which contains some sensible defaults. You can check the default values on the local.tf file. If there still is anything other that needs to be customized, you can always pass on configuration values using the variable helm_values.

Type: any

Default: {}

Outputs

The following outputs are exported:

id

Description: ID to pass other modules in order to refer to this module as a dependency. It takes the ID that comes from the main module and passes it along to the code that called this variant in the first place.

Reference in table format

Show tables

= Requirements

Name Version

argocd

>= 5

null

>= 3

random

>= 3

utils

>= 1

= Providers

Name Version

azurerm

n/a

= Modules

Name Source Version

thanos

= Resources

Name Type

azurerm_federated_identity_credential.thanos

resource

azurerm_role_assignment.storage_contributor

resource

azurerm_user_assigned_identity.thanos

resource

azurerm_resource_group.node_resource_group

data source

azurerm_storage_container.container

data source

= Inputs

Name Description Type Default Required

metrics_storage

Azure Blob Storage configuration for metric archival.

 
object({
    container                        = string
    storage_account                  = string
    managed_identity_node_rg_name    = optional(string, null)
    managed_identity_oidc_issuer_url = optional(string, null)
    storage_account_key              = optional(string, null)
  })

n/a

yes

cluster_name

Name given to the cluster. Value used for the ingress' URL of the application.

string

n/a

yes

base_domain

Base domain of the cluster. Value used for the ingress' URL of the application.

string

n/a

yes

argocd_project

Name of the Argo CD AppProject where the Application should be created. If not set, the Application will be created in a new AppProject only for this Application.

string

null

no

argocd_labels

Labels to attach to the Argo CD Application resource.

map(string)

{}

no

destination_cluster

Destination cluster where the application should be deployed.

string

"in-cluster"

no

target_revision

Override of target revision of the application chart.

string

"v2.7.0"

no

cluster_issuer

SSL certificate issuer to use. Usually you would configure this value as letsencrypt-staging or letsencrypt-prod on your root *.tf files.

string

"selfsigned-issuer"

no

helm_values

Helm chart value overrides. They should be passed as a list of HCL structures.

any

[]

no

deep_merge_append_list

A boolean flag to enable/disable appending lists instead of overwriting them.

bool

false

no

app_autosync

Automated sync options for the Argo CD Application resource.

 
object({
    allow_empty = optional(bool)
    prune       = optional(bool)
    self_heal   = optional(bool)
  })
 
{
  "allow_empty": false,
  "prune": true,
  "self_heal": true
}

no

dependency_ids

IDs of the other modules on which this module depends on.

map(string)

{}

no

thanos

Most frequently used Thanos settings. This variable is merged with the local value thanos_defaults, which contains some sensible defaults. You can check the default values on the local.tf file. If there still is anything other that needs to be customized, you can always pass on configuration values using the variable helm_values.

any

{}

no

= Outputs

Name Description

id

ID to pass other modules in order to refer to this module as a dependency. It takes the ID that comes from the main module and passes it along to the code that called this variant in the first place.