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Configuring the Cluster Log Forwarder for CloudWatch Logs and STS


Authors: Paul Czarkowski, Connor Wooley
Last Editor: Dustin Scott
Published Date: 19 August 2022
Modified Date: 25 May 2023


This guide shows how to deploy the Cluster Log Forwarder operator and configure it to use STS authentication to forward logs to CloudWatch.

Prerequisites

  • A ROSA cluster (configured with STS)
  • The jq cli command
  • The aws cli command

Environment Setup

  1. Configure the following environment variables

    Change the cluster name to match your ROSA cluster and ensure you’re logged into the cluster as an Administrator. Ensure all fields are outputted correctly before moving on.

    export ROSA_CLUSTER_NAME=$(oc get infrastructure cluster -o=jsonpath="{.status.infrastructureName}"  | sed 's/-[a-z0-9]\+$//')
    export REGION=$(rosa describe cluster -c ${ROSA_CLUSTER_NAME} --output json | jq -r .region.id)
    export OIDC_ENDPOINT=$(oc get authentication.config.openshift.io cluster -o json | jq -r .spec.serviceAccountIssuer | sed  's|^https://||')
    export AWS_ACCOUNT_ID=`aws sts get-caller-identity --query Account --output text`
    export AWS_PAGER=""
    export SCRATCH="/tmp/${ROSA_CLUSTER_NAME}/clf-cloudwatch-sts"
    mkdir -p ${SCRATCH}
    echo "Cluster: ${ROSA_CLUSTER_NAME}, Region: ${REGION}, OIDC Endpoint: ${OIDC_ENDPOINT}, AWS Account ID: ${AWS_ACCOUNT_ID}"
    

Prepare AWS Account

  1. Create an IAM Policy for OpenShift Log Forwarding

    POLICY_ARN=$(aws iam list-policies --query "Policies[?PolicyName=='RosaCloudWatch'].{ARN:Arn}" --output text)
    if [[ -z "${POLICY_ARN}" ]]; then
    cat << EOF > ${SCRATCH}/policy.json
    {
    "Version": "2012-10-17",
    "Statement": [
       {
             "Effect": "Allow",
             "Action": [
                "logs:CreateLogGroup",
                "logs:CreateLogStream",
                "logs:DescribeLogGroups",
                "logs:DescribeLogStreams",
                "logs:PutLogEvents",
                "logs:PutRetentionPolicy"
             ],
             "Resource": "arn:aws:logs:*:*:*"
       }
    ]
    }
    EOF
    POLICY_ARN=$(aws iam create-policy --policy-name "RosaCloudWatch" \
    --policy-document file:///${SCRATCH}/policy.json --query Policy.Arn --output text)
    fi
    echo ${POLICY_ARN}
    
  2. Create an IAM Role trust policy for the cluster

    cat <<EOF > ${SCRATCH}/trust-policy.json
    {
       "Version": "2012-10-17",
       "Statement": [{
         "Effect": "Allow",
         "Principal": {
           "Federated": "arn:aws:iam::${AWS_ACCOUNT_ID}:oidc-provider/${OIDC_ENDPOINT}"
         },
         "Action": "sts:AssumeRoleWithWebIdentity",
         "Condition": {
           "StringEquals": {
             "${OIDC_ENDPOINT}:sub": "system:serviceaccount:openshift-logging:logcollector"
           }
         }
       }]
    }
    EOF
    ROLE_ARN=$(aws iam create-role --role-name "${ROSA_CLUSTER_NAME}-RosaCloudWatch" \
       --assume-role-policy-document file://${SCRATCH}/trust-policy.json \
       --query Role.Arn --output text)
    echo ${ROLE_ARN}
    
  3. Attach the IAM Policy to the IAM Role

    aws iam attach-role-policy --role-name "${ROSA_CLUSTER_NAME}-RosaCloudWatch" \
    --policy-arn ${POLICY_ARN}
    

Deploy Operators

  1. Deploy the Cluster Logging operator

    cat << EOF | oc apply -f -
    apiVersion: operators.coreos.com/v1alpha1
    kind: Subscription
    metadata:
      labels:
       operators.coreos.com/cluster-logging.openshift-logging: ""
      name: cluster-logging
      namespace: openshift-logging
    spec:
      channel: stable
      installPlanApproval: Automatic
      name: cluster-logging
      source: redhat-operators
      sourceNamespace: openshift-marketplace
    EOF
    
  2. Create a secret

    cat << EOF | oc apply -f -
    apiVersion: v1
    kind: Secret
    metadata:
      name: cloudwatch-credentials
      namespace: openshift-logging
    stringData:
      role_arn: $ROLE_ARN
    EOF
    

Configure Cluster Logging

  1. Create a cluster log forwarding resource

    cat << EOF | oc apply -f -
    apiVersion: "logging.openshift.io/v1"
    kind: ClusterLogForwarder
    metadata:
      name: instance
      namespace: openshift-logging
    spec:
      outputs:
        - name: cw
          type: cloudwatch
          cloudwatch:
            groupBy: namespaceName
            groupPrefix: rosa-${ROSA_CLUSTER_NAME}
            region: ${REGION}
          secret:
            name: cloudwatch-credentials
      pipelines:
         - name: to-cloudwatch
           inputRefs:
             - infrastructure
             - audit
             - application
           outputRefs:
             - cw
    EOF
    
  2. Create a cluster logging resource

    cat << EOF | oc apply -f -
    apiVersion: logging.openshift.io/v1
    kind: ClusterLogging
    metadata:
      name: instance
      namespace: openshift-logging
    spec:
      collection:
        logs:
           type: fluentd
      forwarder:
        fluentd: {}
      managementState: Managed
    EOF
    

Check AWS CloudWatch for logs

  1. Use the AWS console or CLI to validate that there are log streams from the cluster

    Note: If this is a fresh cluster you may not see a log group for application logs as there are no applications running yet.

    aws logs describe-log-groups --log-group-name-prefix rosa-${ROSA_CLUSTER_NAME}
    
    {
       "logGroups": [
          {
                "logGroupName": "rosa-xxxx.audit",
                "creationTime": 1661286368369,
                "metricFilterCount": 0,
                "arn": "arn:aws:logs:us-east-2:xxxx:log-group:rosa-xxxx.audit:*",
                "storedBytes": 0
          },
          {
                "logGroupName": "rosa-xxxx.infrastructure",
                "creationTime": 1661286369821,
                "metricFilterCount": 0,
                "arn": "arn:aws:logs:us-east-2:xxxx:log-group:rosa-xxxx.infrastructure:*",
                "storedBytes": 0
          }
       ]
    }
    

Cleanup

  1. Delete the Cluster Log Forwarding resource

    oc delete -n openshift-logging clusterlogforwarder instance
    
  2. Delete the Cluster Logging resource

    oc delete -n openshift-logging clusterlogging instance
    
  3. Detach the IAM Policy to the IAM Role

    aws iam detach-role-policy --role-name "${ROSA_CLUSTER_NAME}-RosaCloudWatch" \
    --policy-arn "${POLICY_ARN}"
    
  4. Delete the IAM Role

    aws iam delete-role --role-name "${ROSA_CLUSTER_NAME}-RosaCloudWatch"
    
  5. Delete the IAM Policy

    Only run this command if there are no other resources using the Policy

    aws iam delete-policy --policy-arn "${POLICY_ARN}"
    
  6. Delete the CloudWatch Log Groups

    aws logs delete-log-group --log-group-name "rosa-${ROSA_CLUSTER_NAME}.audit"
    aws logs delete-log-group --log-group-name "rosa-${ROSA_CLUSTER_NAME}.infrastructure"