Enable auto-upgrades for existing Docker Delegates

Learn how to migrate existing Docker delegates to enable automatic upgrades using the Docker Delegate Upgrader script.

Harness now supports automatic upgrades for Docker delegates using the Docker Delegate Upgrader. If you have already running Docker delegates, you can use the script provided below to enable the upgrader for your delegates.

The following approach will only be applicable to Docker delegates that were brought up directly using the docker run command and not for the ones that were started using Docker Compose, Docker Swarm etc.

How It Works

This script performs the following actions:

1. Identifies Harness delegates with the DELEGATE_NAME environment variable. If this environment variable is not set, upgrader will not be able to upgrade such delegates.

2. Starts a lightweight upgrader container for each eligible delegate. The script will run one upgrader for every unique value of DELEGATE_NAME environment variable.

3. Publishes the status of upgrade for every eligible Docker Delegate.

Once run, the upgrader enables periodic checks and automatic updates (if available) for each delegate.

Run the helper Script

Save the following script to a file. Let's say enable-upgrader.sh:

Script

#!/bin/bash

echo "🔍 Scanning all running containers for Harness delegates with DELEGATE_NAME..."

running_containers=$(docker ps --filter "status=running" --format "{{.ID}}")

started_upgraders=()
patched_count=0

for container_id in $running_containers; do
  env_vars=$(docker inspect "$container_id" --format '{{range .Config.Env}}{{println .}}{{end}}')
  DELEGATE_NAME=$(echo "$env_vars" | grep '^DELEGATE_NAME=' | cut -d'=' -f2-)
  DELEGATE_TOKEN=$(echo "$env_vars" | grep '^DELEGATE_TOKEN=' | cut -d'=' -f2-)
  ACCOUNT_ID=$(echo "$env_vars" | grep '^ACCOUNT_ID=' | cut -d'=' -f2-)
  MANAGER_HOST_AND_PORT=$(echo "$env_vars" | grep '^MANAGER_HOST_AND_PORT=' | cut -d'=' -f2-)

  if [ -z "$DELEGATE_NAME" ]; then
    echo "🚫 Container $container_id skipped: no DELEGATE_NAME found."
    continue
  fi

  if [[ " ${started_upgraders[@]} " =~ " ${DELEGATE_NAME} " ]]; then
    echo "🔁 Upgrader for DELEGATE_NAME='$DELEGATE_NAME' already handled. Skipping..."
    continue
  fi

  if docker ps --format '{{.Names}}' | grep -q "^${DELEGATE_NAME}-upgrader$"; then
    echo "⚠️ Upgrader container '${DELEGATE_NAME}-upgrader' already running. Skipping creation."
  else
    echo "🚀 Starting upgrader container for '$DELEGATE_NAME'..."
    docker run -d --cpus=0.1 --memory=100m \
      -v /var/run/docker.sock:/var/run/docker.sock \
      -e ACCOUNT_ID="$ACCOUNT_ID" \
      -e MANAGER_HOST_AND_PORT="$MANAGER_HOST_AND_PORT" \
      -e UPGRADER_WORKLOAD_NAME="$DELEGATE_NAME" \
      -e UPGRADER_TOKEN="$DELEGATE_TOKEN" \
      -e SCHEDULE="0 */1 * * *" \
      us-docker.pkg.dev/gar-prod-setup/harness-public/harness/upgrader:latest

    echo "✅ Upgrader started for '$DELEGATE_NAME'"
    patched_count=$((patched_count + 1))
  fi

  started_upgraders+=("$DELEGATE_NAME")
done

echo "🎉 Finished. Total new upgraders started: $patched_count"

Make the script executable and run it:

chmod +x enable-upgrader.sh
./enable-upgrader.sh

---

Example Output

🔍 Scanning all running containers for Harness delegates with DELEGATE_NAME...
🚀 Starting upgrader container for 'my-delegate'...
Unable to find image 'us-west1-docker.pkg.dev/gar-setup/docker/upgrader:STO_SCAN' locally
STO_SCAN: Pulling from gar-setup/docker/upgrader
42b08cdb6b32: Pull complete
0d5086ce5582: Pull complete
Digest: sha256:ef4df5e448b10e5702f0a4fb6c199f50bd2e3592271272b6f2c55c5e0cb71625
Status: Downloaded newer image for us-west1-docker.pkg.dev/gar-setup/docker/upgrader:latest
1543159cab2f300d3aab3b9446cd5172916a395463f6c4d6f8304e55fc0361ca
✅ Upgrader started for 'my-delegate'
🔁 Upgrader for DELEGATE_NAME='docker-delegate' already handled. Skipping...
🎉 Finished. Total new upgraders started: 1