This plugin allows having multiple Gerrit masters to be deployed across various sites without having to share any storage. The alignment between the masters happens using the replication plugin and an external message broker.
The Gerrit masters requirements are:
Currently, the only mode supported is one primary read/write master and multiple read-only masters but eventually the plan is to support N read/write masters. The read/write master is handling any traffic while the read-only masters are serving the Gerrit GUI assets, the HTTP GET REST API and the git-upload-packs. The read-only masters are kept updated to be always ready to become a read/write master.
For more details on the overall multi-site design and roadmap, please refer to the multi-site plugin DESIGN.md document
This plugin is released under the same Apache 2.0 license and copyright holders as of the Gerrit Code Review project.
The multi-site plugin is built like any other Gerrit plugin in tree mode, by cloning Gerrit and the multi-site plugin code, and checking them out on the desired branch.
Example of cloning Gerrit and multi-site for a stable-2.16 build:
git clone -b stable-2.16 https://gerrit.googlesource.com/gerrit git clone -b stable-2.16 https://gerrit.googlesource.com/plugins/multi-site cd gerrit/plugins ln -s ../../multi-site . rm external_plugin_deps.bzl ln -s multi-site/external_plugin_deps.bzl .
Example of building the multi-site plugin:
cd gerrit bazel build plugins/multi-site
The multi-site.jar plugin is generated to bazel-genfiles/plugins/multi-site/multi-site.jar.
Example of testing the multi-site plugin:
cd gerrit bazel test plugins/multi-site:multi_site_tests
NOTE: The multi-site tests include also the use of Docker containers for instantiating and using a Kafka/Zookeeper broker. Make sure you have a Docker daemon running (/var/run/docker.sock accessible) or a DOCKER_HOST pointing to a Docker server.
Install the multi-site plugin into the $GERRIT_SITE/plugins directory of all the Gerrit servers that are part of the multi-site cluster.
Create the $GERRIT_SITE/etc/multi-site.config on all Gerrit servers with the following basic settings:
[kafka] bootstrapServers = <kafka-host>:<kafka-port> [kafka "publisher"] enabled = true [kafka "subscriber"] enabled = true
For more details on the configuration settings, please refer to the multi-site configuration documentation.
You need also to setup the Git-level replication between nodes, for more details please refer to the replication plugin documentation.