Table of Contents

Object Storage #

Thanos supports any object stores that can be implemented against Thanos objstore.Bucket interface

All clients are configured using --objstore.config-file to reference to the configuration file or --objstore.config to put yaml config directly.

How to use config flags? #

You can either pass YAML file defined below in --objstore.config-file or pass the YAML content directly using --objstore.config. We recommend the latter as it gives an explicit static view of configuration for each component. It also saves you the fuss of creating and managing additional file.

Don’t be afraid of multiline flags!

In Kubernetes it is as easy as (on Thanos sidecar example):

      - args:
        - sidecar
        - |
          --objstore.config=type: GCS
            bucket: <bucket>          
        - --prometheus.url=http://localhost:9090
        - |
          --tracing.config=type: STACKDRIVER
            service_name: ""
            project_id: <project>
            sample_factor: 16          
        - --tsdb.path=/prometheus-data

How to add a new client? #

  1. Create new directory under pkg/objstore/<provider>
  2. Implement objstore.Bucket interface
  3. Add NewTestBucket constructor for testing purposes, that creates and deletes temporary bucket.
  4. Use created NewTestBucket in ForeachStore method to ensure we can run tests against new provider. (In PR)
  5. RUN the TestObjStoreAcceptanceTest against your provider to ensure it fits. Fix any found error until test passes. (In PR)
  6. Add client implementation to the factory in factory code. (Using as small amount of flags as possible in every command)
  7. Add client struct config to bucketcfggen to allow config auto generation.

At that point, anyone can use your provider by spec.

Configuration #

Current object storage client implementations:

ProviderMaturityAuto-tested on CIMaintainers
Google Cloud StorageStable (production usage)yes@bwplotka
AWS/S3Stable (production usage)yes@bwplotka
Azure Storage AccountStable (production usage)no@vglafirov
OpenStack SwiftBeta (working PoCs, testing usage)no@sudhi-vm
Tencent COSBeta (testing usage)no@jojohappy
AliYun OSSBeta (testing usage)no@shaulboozhiao,@wujinhu
Local FilesystemBeta (testing usage)yes@bwplotka

NOTE: Currently Thanos requires strong consistency (write-read) for object store implementation.

S3 #

Thanos uses the minio client library to upload Prometheus data into AWS S3.

You can configure an S3 bucket as an object store with YAML, either by passing the configuration directly to the --objstore.config parameter, or (preferably) by passing the path to a configuration file to the --objstore.config-file option.

NOTE: Minio client was mainly for AWS S3, but it can be configured against other S3-compatible object storages e.g Ceph

type: S3
  bucket: ""
  endpoint: ""
  region: ""
  access_key: ""
  insecure: false
  signature_version2: false
  encrypt_sse: false
  secret_key: ""
  put_user_metadata: {}
    idle_conn_timeout: 90s
    response_header_timeout: 2m
    insecure_skip_verify: false
    enable: false
  part_size: 134217728

At a minimum, you will need to provide a value for the bucket, endpoint, access_key, and secret_key keys. The rest of the keys are optional.

The AWS region to endpoint mapping can be found in this link.

Make sure you use a correct signature version. Currently AWS requires signature v4, so it needs signature_version2: false. If you don’t specify it, you will get an Access Denied error. On the other hand, several S3 compatible APIs use signature_version2: true.

You can configure the timeout settings for the HTTP client by setting the http_config.idle_conn_timeout and http_config.response_header_timeout keys. As a rule of thumb, if you are seeing errors like timeout awaiting response headers in your logs, you may want to increase the value of http_config.response_header_timeout.

Please refer to the documentation of the Transport type in the net/http package for detailed information on what each option does.

part_size is specified in bytes and refers to the minimum file size used for multipart uploads, as some custom S3 implementations may have different requirements. A value of 0 means to use a default 128 MiB size.

For debug and testing purposes you can set

  • insecure: true to switch to plain insecure HTTP instead of HTTPS

  • http_config.insecure_skip_verify: true to disable TLS certificate verification (if your S3 based storage is using a self-signed certificate, for example)

  • trace.enable: true to enable the minio client’s verbose logging. Each request and response will be logged into the debug logger, so debug level logging must be enabled for this functionality.

Credentials #

By default Thanos will try to retrieve credentials from the following sources:

  1. From config file if BOTH access_key and secret_key are present.
  2. From the standard AWS environment variable - AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY
  3. From ~/.aws/credentials
  4. IAM credentials retrieved from an instance profile.

NOTE: Getting access key from config file and secret key from other method (and vice versa) is not supported.

AWS Policies #

Example working AWS IAM policy for user:

  • For deployment (policy for Thanos services):
    "Version": "2012-10-17",
    "Statement": [
            "Sid": "Statement",
            "Effect": "Allow",
            "Action": [
            "Resource": [

(No bucket policy)

To test the policy, set env vars for S3 access for empty, not used bucket as well as:


And run: GOCACHE=off go test -v -run TestObjStore_AcceptanceTest_e2e ./pkg/...

  • For testing (policy to run e2e tests):

We need access to CreateBucket and DeleteBucket and access to all buckets:

    "Version": "2012-10-17",
    "Statement": [
            "Sid": "Statement",
            "Effect": "Allow",
            "Action": [
            "Resource": [

With this policy you should be able to run set THANOS_TEST_OBJSTORE_SKIP=GCS,AZURE,SWIFT,COS,ALIYUNOSS and unset S3_BUCKET and run all tests using make test.

Details about AWS policies:


To configure Google Cloud Storage bucket as an object store you need to set bucket with GCS bucket name and configure Google Application credentials.

For example:

type: GCS
  bucket: ""
  service_account: ""


Application credentials are configured via JSON file and only the bucket needs to be specified, the client looks for:

  1. A JSON file whose path is specified by the GOOGLE_APPLICATION_CREDENTIALS environment variable.
  2. A JSON file in a location known to the gcloud command-line tool. On Windows, this is %APPDATA%/gcloud/application_default_credentials.json. On other systems, $HOME/.config/gcloud/application_default_credentials.json.
  3. On Google App Engine it uses the appengine.AccessToken function.
  4. On Google Compute Engine and Google App Engine Managed VMs, it fetches credentials from the metadata server. (In this final case any provided scopes are ignored.)

You can read more on how to get application credential json file in

Using inline a Service Account #

Another possibility is to inline the ServiceAccount into the Thanos configuration and only maintain one file. This feature was added, so that the Prometheus Operator only needs to take care of one secret file.

type: GCS
  bucket: "thanos"
  service_account: |-
      "type": "service_account",
      "project_id": "project",
      "private_key_id": "abcdefghijklmnopqrstuvwxyz12345678906666",
      "private_key": "-----BEGIN PRIVATE KEY-----\...\n-----END PRIVATE KEY-----\n",
      "client_email": "",
      "client_id": "123456789012345678901",
      "auth_uri": "",
      "token_uri": "",
      "auth_provider_x509_cert_url": "",
      "client_x509_cert_url": ""

GCS Policies #

Note: GCS Policies should be applied at the project level, not at the bucket level

For deployment:

Storage Object Creator and Storage Object Viewer

For testing:

Storage Object Admin for ability to create and delete temporary buckets.

To test the policy is working as expected, exec into the sidecar container, eg:

kubectl exec -it -n <namespace> <prometheus with sidecar pod name> -c <sidecar container name> -- /bin/sh

Then test that you can at least list objects in the bucket, eg:

thanos bucket ls --objstore.config="${OBJSTORE_CONFIG}"

Azure #

To use Azure Storage as Thanos object store, you need to precreate storage account from Azure portal or using Azure CLI. Follow the instructions from Azure Storage Documentation:

To configure Azure Storage account as an object store you need to provide a path to Azure storage config file in flag --objstore.config-file.

Config file format is the following:

type: AZURE
  storage_account: ""
  storage_account_key: ""
  container: ""
  endpoint: ""
  max_retries: 0

OpenStack Swift #

Thanos uses gophercloud client to upload Prometheus data into OpenStack Swift.

Below is an example configuration file for thanos to use OpenStack swift container as an object store. Note that if the name of a user, project or tenant is used one must also specify its domain by ID or name. Various examples for OpenStack authentication can be found in the official documentation.

type: SWIFT
  auth_url: ""
  username: ""
  user_domain_name: ""
  user_domain_id: ""
  user_id: ""
  password: ""
  domain_id: ""
  domain_name: ""
  project_id: ""
  project_name: ""
  project_domain_id: ""
  project_domain_name: ""
  region_name: ""
  container_name: ""

Tencent COS #

To use Tencent COS as storage store, you should apply a Tencent Account to create an object storage bucket at first. Note that detailed from Tencent Cloud Documents:

To configure Tencent Account to use COS as storage store you need to set these parameters in yaml format stored in a file:

type: COS
  bucket: ""
  region: ""
  app_id: ""
  secret_key: ""
  secret_id: ""

Set the flags --objstore.config-file to reference to the configuration file.

AliYun OSS #

In order to use AliYun OSS object storage, you should first create a bucket with proper Storage Class , ACLs and get the access key on the AliYun cloud. Go to for more detail.

To use AliYun OSS object storage, please specify following yaml configuration file in objstore.config* flag.

  endpoint: ""
  bucket: ""
  access_key_id: ""
  access_key_secret: ""

Use –objstore.config-file to reference to this configuration file.

Filesystem #

This storage type is used when user wants to store and access the bucket in the local filesystem. We treat filesystem the same way we would treat object storage, so all optimization for remote bucket applies even though, we might have the files locally.

NOTE: This storage type is experimental and might be inefficient. It is NOT advised to use it as the main storage for metrics in production environment. Particularly there is no planned support for distributed filesystems like NFS. This is mainly useful for testing and demos.

  directory: ""