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Frequently Asked Questions

Terminology

  • What is a Kubernetes Operator?

    Operators are software extensions to Kubernetes that make use of custom resources to manage applications and their components. More information is in the Kubernetes Documentation.

  • What is a Kubernetes Controller?

    In Kubernetes, controllers are control loops that watch the state of your cluster, then make or request changes where needed. Each controller tries to move the current cluster state closer to the desired state. More information is in the Kubernetes Documentation.

  • What is a Kubernetes Custom Resource?

    Custom resources are extensions of the Kubernetes API. More information is in the Kubernetes Documentation.

General Questions

  • What is the difference between Terraform Cloud Operator and HCP Terraform Operator?

    The HCP Terraform Operator was developed to address some major concerns that we encountered in the first version.

    Here is the list of major improvements in the HCP Terraform Operator compared to its predecessor, the Terraform Cloud Operator:

    • A new operator option --namespace allows configuration of namespaces to watch. It can be one of the following: all, single, or multiple namespaces. By default, the Operator watches all namespaces, and as your setup grows, you can have multiple deployments of the Operator to better handle the load.

    • A new operator option --sync-period allows configuration of the minimum frequency at which all watched resources are reconciled. This allows faster synchronization of the state between Custom Resources and HCP Terraform.

    • The Operator manages a HCP Terraform client for each Custom Resource. This means that a single deployment of the Operator can work across multiple HCP Terraform organizations.

    • The Operator consists of multiple controllers that manage different HCP Terraform resources. This provides additional flexibility, e.g. a module can be executed in a workspace that is not managed by the Operator. More details about controllers you can find in the README file.

    • Each controller has the option to manage the number of workers it has. By default, each controller has 1 worker. A worker is a thread that runs the control loop for a given Custom Resource. The more workers the controller has, the more Customer Resources it can handle concurrently. This improves the Operator's performance. Please refer to the performance FAQ section to better understand the pros and cons.

    • Additional technical improvements:

      • More detailed logging.

      • Controllers produce event messages for each Custom Resource.

      • Better coverage of features supported by HCP Terraform, more information here.

      • Better test coverage.

      • A leaner "Distroless" container image for deployment that is built for more platforms. More information here.

  • Can a single deployment of the Operator watch single, multiple, or all namespaces?

    Yes, a single deployment of the Operator can either watch a single namespace, multiple namespaces, or all namespaces in the Kubernetes cluster. By default, the Operator watches all namespaces. If you want to specify single or multiple namespaces, you need to pass the following option when installing or upgrading the Helm chart.

    watch a single namespace

    $ helm ... --set 'operator.watchedNamespaces={red}'

    watch multiple namespaces

    $ helm ... --set 'operator.watchedNamespaces={white,blue,red}'

  • What will happen if I have multiple deployments of the Operator watching the same namespace(s)?

    Unexpected behaviour is likely when multiple deployments of the operator try to reconcile the same resource. Most likely you will notice that Customer Resource objects are constantly reconciled and this can cause constant updates of HCP Terraform objects. For example, the Module controller might trigger a new run every reconciliation and because of that the Run queue could grow infinitely.

    It is definitely better to avoid such situations.

  • What do the *-workers options do?

    The *-workers options allow configuration of the number of concurrent workers available to process changes to resources. In certain cases increasing this number can improve performance.

  • What do the *-sync-period options do?

    The --sync-period is a global operator option that specifies the minimum frequency at which all watched resources of all controllers are reconciled at once.

    The --workspace-sync-period is a Workspace controller option that specifies the time interval for requeuing Workspace resources, ensuring they will be reconciled. This time is set individually per resource and it helps avoid spike of the resources to reconcile.

    The controller synchronization period should be aligned with the number of managed Customer Resources. If the period is too low and the number of managed resources is too high, you may observe slowness in synchronization.

    The value of sync-period should be higher than the value of *-sync-period.

  • Does the Operator work with Terraform Enterprise / TFE?

    Yes, the operator can be configured to use the custom TFE API endpoint using the operator.tfeAddress value in the Helm chart. This value should be a valid URL including the protocol(https://), for the API of a Terraform Enterprise instance. Once the operator.tfeAddress attribute is set, the operator will no longer access the public HCP Terraform, but rather the private Terraform Enterprise instance.

  • What can I do if the Operator cannot get a HCP Terraform client due to a TLS certificate issue?

    There are multiple reasons why you may observe an error message in logs that indicate an issue with a TLS certificate. The error message example: tls: failed to verify certificate: x509: certificate has expired or is not yet valid

    • You have a Terraform Enterprise instance and use the TLS certificate that is signed by a Certificate Authority that is not recognized by the Operator. In this case, you can use the value customCAcertificates of the Helm chart to specify a Certificate Authority bundle to validate API TLS certificates.
    • You have a Terraform Enterprise instance and the TLS certificate has expired. In this case, you can use the value operator.skipTLSVerify of the Helm chart to skip the TLS validation. Be aware of the potential security risks.
    • There is a TLS proxy between the Operator and HCP Terraform / Enterprise instance that is installed by your security team to decrypt TLS connections. In this case, you can use the value operator.skipTLSVerify or customCAcertificates of the Helm chart to skip the TLS validation or specify a Certificate Authority bundle to validate API TLS certificates, respectively. Alternatively, you could talk to your security team to add an expection to this connection.

  • What does kube-rbac-proxy do?

    The kube-rbac-proxy is a small HTTP proxy for a single upstream, that can perform RBAC authorization against the Kubernetes API. This allows providing RBAC-based access to the operator metrics within the Kubernetes cluster. More information is in the author's blog post.

  • Why can't I use newly added fields and CRDs after the upgrade?

    The main reason here is that Helm does not upgrade CRDs when the upgrade operation is performed. This affects both scenarios: when an existing CRD is updated and when a new controller, and thus a new CRD, is added. In both cases, manual steps are required to add a new CRD or upgrade the existing one.

    When a new version of the Operator adds a new controller and, consequently, a new CRD, the following steps must be performed for a smooth update:

    1. Create an environment variable that will contain the target version:

      $ export TFC_OPERATOR_VERSION=2.2.0

    2. Install the new CRD from the target release:

      $ kubectl apply -f https://raw.githubusercontent.com/hashicorp/terraform-cloud-operator/v$TFC_OPERATOR_VERSION/charts/terraform-cloud-operator/crds/app.terraform.io_projects.yaml

    3. Upgrade the Operator via Helm:

      $ helm upgrade <RELEASE-NAME> hashicorp/terraform-cloud-operator --version $TFC_OPERATOR_VERSION <ADDITIONAL-OPTIONS>

    In the above example, the target version is set to 2.2.0. This version introduces a new controller, Project, the CRD of which we have installed.

    When a new version of the Operator modifies an existing CRD schema, the following steps must be performed for a smooth update:

    1. Create an environment variable that will contain the target version:

      $ export TFC_OPERATOR_VERSION=2.1.0

    2. Replace the existing CRD with the new one from the target release:

      $ kubectl replace -f https://raw.githubusercontent.com/hashicorp/terraform-cloud-operator/v$TFC_OPERATOR_VERSION/charts/terraform-cloud-operator/crds/app.terraform.io_workspaces.yaml

    3. Upgrade the Operator via Helm:

      $ helm upgrade <RELEASE-NAME> hashicorp/terraform-cloud-operator --version $TFC_OPERATOR_VERSION <ADDITIONAL-OPTIONS>

    In the above example, the target version is set to 2.1.0. This version introduces a new field, spec.project.[id | name], to the Workspace controller, the CRD of which we have replaced.

Performance

  • How many Custom Resources can be managed by a single deployment of the Operator?

    In theory, a single deployment of the Operator can manage thousands of resources. However, the Operator's performance depends on the number of API calls it does and the HCP Terraform API rate limit for the token used.

    The number of API calls the Operator does depends on multiple factors:

    • The value of the sync-period option.

    • The values of *-workers options.

    • The type of the resource.

    • The HCP Terraform features being used.

    With the default values of sync-period (5 minutes) and *-workers (1 worker per controller), we recommend managing 100 resources per token. This number can vary based on previously mentioned factors. This number can be updated later to accommodate changes in the HCP Terraform API.

  • What can be done to improve performance?

    The Operator allows you to refer to HCP Terraform resources by their name or ID. For example, the Workspace controller allows you to specify another workspace to use as a Run Trigger. It accepts a list of workspaces that will be triggered where each item can either be the ID or Name of the workspace. When you use a name, the Operator does an API call on each reconciliation in order to get the ID of the target Workspace. This makes configurations easier to read, but causes more API calls to be as the operator needs to figure out what the ID of workspace is from the name.

    One way to improve performance is to use the referred object ID. In this example, by the Workspace ID. In this case, the Operator will use the ID directly without trying to resolve it.

    Here is a short example to demonstrate both options:

    apiVersion: app.terraform.io/v1alpha2
kind: Workspace
metadata:
name: this
spec:
  runTriggers:
    - id: ws-NUVHA9feCXzAmPHx
    - name: target-workspace

    Please refer to the CRDs and API Reference to see if the feature you use supports ID or Name.

Agent Pool Controller

  • Where can I find Agent tokens?

    The Agent tokens are sensitive and will be saved in a Secret. The name of the Secret object will be generated automatically and has the following pattern: <metadata.name>-agent-pool.

  • Does the Operator restore tokens if I delete the whole Secret containing the Agent Tokens or a single token from it?

    No. You will have to update the Custom Resource to re-create tokens.

  • What will happen if I delete an Agent Pool Customer Resource?

    The Agent Pool controller will delete Agent Pool from HCP Terraform, as well as the Kubernetes Secret that stores the Agent Tokens that were generated for this pool.

  • What triggers Agents scaling?

    The Operator regularly monitors specific workspaces and boosts the agent count when pending runs are detected. The maximum number of agents can be increased up to the value defined in autoscaling.maxReplicas or limited by the license, depending on which limit is reached first. If there are no pending runs, the Operator will reduce the number of agents to the specified value in autoscaling.minReplicas within the timeframe of autoscaling.cooldownPeriodSeconds.

Module Controller

  • Where can I find Module outputs?

    Non-sensitive outputs will be saved in a ConfigMap. Sensitive outputs will be saved in a Secret. In both cases, the name of the corresponding Kubernetes object will be generated automatically and has the following pattern: <metadata.name>-module-outputs. When the underlying workspace is managed by the operator, all outputs will be duplicated in the corresponding ConfigMap or Secret.

  • Can I execute a new Run without changing any Workspace or Module attributes?

    Yes. There is a special attribute spec.restartedAt that you need to update in order to trigger a new Run execution. For example:

    $ kubectl patch module <NAME> --type=merge --patch '{"spec": {"restartedAt": "'`date -u -Iseconds`'"}}'

Project Controller

  • Can I delete a project that has workspaces in it?

    No, you can only delete a project if it is empty and you have the proper permissions.

Workspace Controller

  • Can a single deployment of the Operator manage the Workspaces of different Organizations?

    Yes. The Workspace resource has mandatory fields spec.organization and spec.token. The Operator manages workspaces based on these credentials.

  • Where can I find Workspace outputs?

    Non-sensitive outputs will be saved in a ConfigMap. Sensitive outputs will be saved in a Secret. In both cases, the name of the corresponding Kubernetes resource will be generated automatically and has the following pattern: <metadata.name>-outputs.

  • What version of Terraform is utilized in the Workplace?

    If the spec.terraformVersion is configured, the Operator ensures that the specified version will be utilized.

    If the spec.terraformVersion is not configured, i.e. empty, the latest available Terraform version will be picked up during the Workspace creation and the same version will be utilized till it gets updated via the Workspace manifest.

    Regardless of the scenario, you can always refer to status.terraformVersion to determine the version of Terraform being used in the Workplace.

  • Can I create a workspace or move the one that already exists to a specific project?

    Yes, you can do this. Bear in mind that a project must exist before referring to it; otherwise, the create or update operation will fail:

    • If this is a new workspace and the referred project doesn’t exist, the workspace creation will fail with a corresponding error/event message.

    • If this involves migrating an existing workspace and the referred project doesn’t exist, the workspace will remain within the same project, and a corresponding error/event message will be provided.

    If the spec.project field is not specified, the workspace will be created or moved to the default project.