Run multiple agents on the same host

It is possible to run multiple GoCD agents on the same host.

Each agent needs to be configured to run in its own separate directory so that each agent can build independently of the other, and also keep their config files separate. Follow the instructions below to configure multiple GoCD agents on the same host.

Linux package installed using apt/dpkg/rpm/yum

First, verify if you installed the package using this method.

On debian/ubuntu:
bash
```
$ dpkg -s go-agent | grep Status
Status: install ok installed
```
On CentOS/RedHat/Fedora and other RPM based distros:
bash
```
$ rpm -qa | grep go-agent
go-agent-{VERSION}.noarch
```
If the package is not installed, make sure to download and install the GoCD agent from https://gocd.org/download.

If the package is installed, run the following script. Be sure to substitute the environment variables AGENT_COUNT, RUN_AS_SERVICE and START_SERVICE_NOW as appropriate.

bash

# spin up 5 additional GoCD agents.
AGENT_COUNT=5

# if you want to run the GoCD agent as a service
RUN_AS_SERVICE=true

# if you want to start the service immediately
# only works if `RUN_AS_SERVICE` is true
START_SERVICE_NOW=true

for AGENT_INDEX in $(seq 1 "${AGENT_COUNT}")
do
  AGENT_ID="go-agent-${AGENT_INDEX}"

  # create the directories for agent data and binaries
  mkdir -p /usr/share/${AGENT_ID} /var/{lib,log}/${AGENT_ID} /var/lib/${AGENT_ID}/run

  # copy over all config and shell scripts and wrapper configs
  cp -arf /usr/share/go-agent/{bin,wrapper-config} /usr/share/${AGENT_ID}

  # symlink the wrapper binaries
  ln -sf /usr/share/go-agent/wrapper /usr/share/${AGENT_ID}

  # change ownership and mode, so that the `go` user, and only that user
  # can write to these directories
  chown -R go:go /var/{lib,log}/${AGENT_ID}
  chmod -R 0750 /var/{lib,log}/${AGENT_ID}
  chmod 0755 /usr/share/${AGENT_ID}

  # tweak the scripts and configs to use the correct directories
  sed -i -e "s@go-agent@${AGENT_ID}@g" \
      /usr/share/${AGENT_ID}/bin/go-agent
  sed -i -e "s@=go-agent\$@=${AGENT_ID}@g" \
         -e "s@/var/lib/go-agent@/var/lib/${AGENT_ID}@g" \
         -e "s@/var/log/go-agent@/var/log/${AGENT_ID}@g" \
         -e "s@../wrapper-config/wrapper-properties.conf@/usr/share/${AGENT_ID}/wrapper-config/wrapper-properties.conf@g" \
      /usr/share/${AGENT_ID}/wrapper-config/wrapper.conf
  sed -i -e "s@/var/lib/go-agent@/var/lib/${AGENT_ID}@g" \
      /usr/share/${AGENT_ID}/wrapper-config/wrapper-properties.conf

  if [ "${RUN_AS_SERVICE}" == "true" ]; then
    if [ "${START_SERVICE_NOW}" == "true" ]; then
      /usr/share/${AGENT_ID}/bin/go-agent installstart
    else
      /usr/share/${AGENT_ID}/bin/go-agent install
    fi
  fi
done

macOS installers

To run multiple macOS installers, run the following script. Be sure to substitute the environment variables AGENT_COUNT, RUN_AS_SERVICE and START_SERVICE_NOW as appropriate.

bash

# spin up 2 additional GoCD agents.
AGENT_COUNT=2

# path to existing agent dir
AGENT_PATH="/path/to/go-agent-X.Y.Z"

for AGENT_INDEX in $(seq 1 "${AGENT_COUNT}")
do
  AGENT_ID="go-agent-${AGENT_INDEX}"

  /bin/mkdir -p "${AGENT_ID}" "${AGENT_ID}/run"

  # use the same jre and GoCD jars from main agent
  /bin/ln -sf "${AGENT_PATH}/jre" "${AGENT_ID}/jre"
  /bin/ln -sf "${AGENT_PATH}/lib" "${AGENT_ID}/lib"

  # copy over the wrapper shell scripts, because they seem to resolve symlinks
  /bin/cp -rf "${AGENT_PATH}/bin" "${AGENT_ID}"
  /bin/cp -rf "${AGENT_PATH}/wrapper" "${AGENT_ID}"
  /bin/cp -rf "${AGENT_PATH}/wrapper-config" "${AGENT_ID}"
done

Package installed on other OSes using the generic ".zip" installer

To run multiple agent instances, extract a copy of the agent zip in a new location and execute it.
If you would like to run these agent processes as windows or Linux/Unix services that start when the machine boots up:

On windows:
- Edit the wrapper-config/wrapper.conf file to set the properties wrapper.name, wrapper.displayname, wrapper.console.title and wrapper.description and set different values for each agent process
On Linux/Unix:
- Edit the wrapper-config/wrapper.conf file to set the properties wrapper.name, wrapper.displayname, wrapper.console.title and wrapper.description and set different values for each agent process
- Edit the file bin/go-agent and replace all occurrences of go-agent with a different value for each agent process. Set the envionment variable RUN_AS_USER=go to ensure that the service runs as the go user.

README Running Multiple Agents

Run multiple agents on the same host

Linux package installed using apt/dpkg/rpm/yum

macOS installers

Package installed on other OSes using the generic ".zip" installer