commit | 93ff9c2c115c9e4b917ac5a4cfc527e275c61336 | [log] [tgz] |
---|---|---|
author | Luca Milanesio <luca.milanesio@gmail.com> | Fri Feb 28 22:40:42 2020 +0000 |
committer | Luca Milanesio <luca.milanesio@gmail.com> | Sat Feb 29 20:03:38 2020 +0000 |
tree | bf54b7fb5e47bb8b46d1525161789b4baf0e8f61 | |
parent | 3faade4713422d94d0ed32adeea8c3a518deb572 [diff] |
Update project version on global ref-db only when more recent The project version (refs/multi-site/version) on the local project is more up-to-date than the one on global ref-db, update unconditionally without requiring the local SHA1 to be the same of the global ref-db. When refs are updated in a short period of time (e.g. refs/multi-site/version and refs/changes/N/NNNN/meta) it is not guaranteed that the replication will be able to push all the intermediate SHA1s. Skipping SHA1s to push for non-fast-forward branches like refs/multi-site/version is a valid use-case and thus can be performed as long as the local version is the most recent one. Failing to update the global ref-db project version causes split-brain with all the other nodes because the replication would filter out the refs out of sync. Bug: Issue 12413 Change-Id: Ib5e49edd3ba37ed60f34736f7af5e5a324248e51
This plugin allows to deploy a distributed cluster of multiple Gerrit masters each using a separate site without sharing any storage. The alignment between the masters happens using the replication plugin and an external message broker.
Requirements for the Gerrit masters are:
NOTE: The multi-site plugin will not start if Gerrit is not yet migrated to NoteDb.
Currently, the only mode supported is one primary read/write master and multiple read-only masters but eventually the plan is to support multiple 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 git fetch requests (git-upload-pack). The read-only masters are kept synchronized with the read/write master in order 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 can only be built 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-bin/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/lib
directory of all the Gerrit servers that are part of the multi-site cluster. Create a symbolic link from $GERRIT_SITE/lib/multi-site.jar
into the $GERRIT_SITE/plugins
.
Add the multi-site module to $GERRIT_SITE/etc/gerrit.config
as follows:
[gerrit] installDbModule = com.googlesource.gerrit.plugins.multisite.GitModule installModule = com.googlesource.gerrit.plugins.multisite.Module
For more details on the configuration settings, please refer to the multi-site configuration documentation.
You also need to setup the Git-level replication between nodes, for more details please refer to the replication plugin documentation.