|author||Fabio Ponciroli <email@example.com>||Fri Oct 22 22:21:33 2021 +0200|
|committer||Fabio Ponciroli <firstname.lastname@example.org>||Mon Oct 25 18:56:55 2021 +0000|
Always update replication status metrics In the following scenario the replication status metrics become stale: * Node1 is serving traffic for projectX,replication lag metrics are empty: => projectX_Node1_local_version = t1, projectX_remote_version = t1, node1_lag=0 => replication lag metric added for projectX-node1 * Node1 is briefly unhelthy and Node2 serves traffic for projectX => projectX_Node1_local_version = t1, projectX_remote_version = t2, node1_lag=t2-t1 => replication lag metric updated for projectX-node1 * Node1 is back and serves traffic for projectX: => projectX_Node1_local_version = t3, projectX_remote_version = t3, node1_lag=0 => replication lag metric is NOT updated for projectX-node1, since the event is coming from Node1 * Node1 continue serving traffic => replication lag metric for projectX-node1 will never be updated and it will always be stale Always update them regardless the origin of the event. Bug: Issue 15168 Change-Id: Ibe4ff24583ccad7b14640f7b251094c3fd2d8f95
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.
Supports multiple read/write masters across multiple sites across different geographic locations. The Gerrit nodes are kept synchronized between each other using the replication plugin and a global ref-database in order to detect and prevent split-brains.
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
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
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.