Migrate from Cortex to Grafana Mimir

As an operator, you can migrate a Helm deployment of Cortex to Grafana Mimir. The overview includes the steps required for any environment. To migrate deployment environments with Helm, see Migrate to Grafana Mimir using Helm.

Note: This document was tested with Cortex versions 1.10 and 1.11. It might work with more recent versions of Cortex, but that is not guaranteed.

To migrate a Jsonnet deployment of Cortex refer to Migrate from Cortex.

Grafana Mimir includes significant changes that simplify the deployment and continued operation of a horizontally scalable, multi-tenant time series database with long-term storage.

The changes make Grafana Mimir easier to run out of the box:

  • Removed configuration parameters that don’t require tuning
  • Renamed some parameters so that they’re more easily understood
  • Updated the default values of some existing parameters

The mimirtool automates configuration conversion. It provides a simple migration by generating Mimir configuration from Cortex configuration.

Before you begin:

  • Ensure that you are running either Cortex 1.10.X or Cortex 1.11.X.

    If you are running an older version of Cortex, upgrade to Cortex 1.11.1 before proceeding with the migration.

  • Ensure you have installed Cortex alerting and recording rules as well as Cortex dashboards.

    Using the monitoring mixin, you need to install both alerting and recording rules in either Prometheus or Cortex. You also need to install dashboards in Grafana. To download a prebuilt ZIP file that contains the alerting and recording rules, refer to Release Cortex-jsonnet 1.11.0.

    To upload rules to the ruler using mimirtool, refer to mimirtool rules. To import the dashboards into Grafana, refer to Import dashboard.

Notable changes

Note: For the full list of changes, refer to Mimir’s CHANGELOG.

  • The Grafana Mimir HTTP server defaults to listening on port 8080; Cortex defaults to listening on port 80. To maintain port 80 as the listening port, set -server.http-listen-port=80.

  • Grafana Mimir uses anonymous as the default tenant ID when -auth.multitenancy=false. Cortex uses fake as the default tenant ID when -auth.enabled=false. Use when -auth.multitenancy=false to match the Cortex default tenant ID.

  • Grafana Mimir removes the legacy HTTP prefixes deprecated in Cortex.

    • Query endpoints

    • Distributor endpoints

      Legacy endpointCurrent
    • Ingester endpoints

    • Ruler endpoints

    • Alertmanager endpoints


Generate the configuration for Grafana Mimir

The mimirtool config convert command converts Cortex configuration to Mimir configuration. You can use it to update both flags and configuration files.

Install mimirtool

To install Mimirtool, download the appropriate binary from the latest release for your operating system and architecture and make it executable.

Alternatively, use a command line tool such as curl to download mimirtool. For example, for Linux with the AMD64 architecture, use the following command:

curl -fLo mimirtool
chmod +x mimirtool

Use mimirtool

The mimirtool config convert command converts Cortex 1.11 configuration files to Grafana Mimir configuration files. It removes any configuration parameters that are no longer available in Grafana Mimir, and it renames configuration parameters that have a new name. If you have explicitly set configuration parameters to a value matching the Cortex default, by default, mimirtool config convert doesn’t update the value. To have mimirtool config convert update explicitly set values from the Cortex defaults to the new Grafana Mimir defaults, provide the --update-defaults flag. Refer to convert for more information on using mimirtool for configuration conversion.

Migrate to Grafana Mimir using Helm

You can migrate to the Grafana Mimir Helm chart (grafana/mimir-distributed v3.1.0) from the Cortex Helm chart (cortex-helm/cortex v1.7.0).

Before you begin

  • Ensure that you are running the v1.7.0 release of the Cortex Helm chart.

  • Ensure that you are running ingesters using a Kubernetes StatefulSet.

  • Install yq v4.

    In the values.yaml file:

        enabled: true

    The ingester needs storage capacity for write-ahead-logging (WAL) and to create blocks for uploading. The WAL was optional in Cortex with chunks, but not optional in Mimir. A StatefulSet is the most convenient way to make sure that each Pod gets a storage volume.

To migrate to the Grafana Mimir Helm chart:

  1. Install the updated monitoring mixin.

    a. Add the dashboards to Grafana. The dashboards replace your Cortex dashboards and continue to work for monitoring Cortex deployments.

    Note: Resource dashboards are now enabled by default and require additional metrics sources. To understand the required metrics sources, refer to Additional resources metrics.

    b. Install the recording and alerting rules into the ruler or a Prometheus server.

  2. Run the following command to add the Grafana Helm chart repository:

    helm repo add grafana
  3. Convert the Cortex configuration in your values.yaml file.

    a. Extract the Cortex configuration and write the output to the cortex.yaml file.

    yq '.config' <VALUES YAML FILE> > cortex.yaml

    b. Use mimirtool to update the configuration.

    mimirtool config convert --yaml-file cortex.yaml --yaml-out mimir.yaml

    c. Clean up the generated YAML configuration.

    You have to remove some fields that are generated by mimirtool config convert or are coming from old configuration, because the mimir-distributed Helm chart has already set the default value for them. Use the following script to clean up those fields:

    yq -i 'del(.activity_tracker.filepath,.alertmanager.data_dir,.compactor.data_dir,.frontend_worker.frontend_address,.ingester.ring.tokens_file_path,.ruler.alertmanager_url,.ruler.rule_path,.runtime_config.file)' mimir.yaml

    d. At the top level of your custom Helm values file, put the updated configuration under the mimir.structuredConfig key.

    Note: The mimir.structuredConfig field, which is added in v3.0.0, allows you to override a specific configuration without needing to rewrite the whole block string literal, such as in mimir.config.

    In your Helm values file:

      structuredConfig: <CONFIGURATION FILE CONTENTS>


            num_tokens: 512

    e. Set the ingester podManagementPolicy to "OrderedReady". The Grafana Mimir chart prefers "Parallel" for faster scale up, but this field is immutable on an existing StatefulSet.

    In your values.yaml file:

      podManagementPolicy: "OrderedReady"

    f. Set the nameOverride parameter to cortex. This configuration parameter ensures that resources have the same names as those created by the Cortex Helm chart and ensures Kubernetes performs a rolling upgrade of existing resources instead of creating new resources.

    In your values.yaml file:

    nameOverride: "cortex"

    g. Disable MinIO. The Grafana Mimir Helm chart enables MinIO by default for convenience during first time install. If you are migrating from Cortex and have your existing object storage you must disable MinIO in Grafana Mimir Helm chart custom values.yaml.

    In your values.yaml file:

      enabled: false
  4. Run the Helm upgrade with the Grafana Mimir chart.

    Note: The name of the release must match your Cortex Helm chart release.

    helm upgrade <RELEASE> grafana/mimir-distributed [-n <NAMESPACE>]

To verify that the cluster is operating correctly, use the monitoring mixin dashboards.