The @PLUGIN@ plugin must be installed as a library module in the $GERRIT_SITE/lib folder of all the instances and linked to $GERRIT_SITE/plugins, which enable to use it as both libModule and plugin. Configuration should be specified in the $site_path/etc/@PLUGIN@.config file.
cache.synchronize : Whether to synchronize cache evictions. Set to false when relying on low cache TTLs and therefore cache eviction is not strictly needed. It requires disabling the background cache evictions notifications in gerrit.config by setting cache.threads = 0.
Defaults to true.
cache.threadPoolSize : Maximum number of threads used to send cache evictions to the target instance.
Defaults to 4.
cache.pattern : Pattern to match names of custom caches for which evictions should be forwarded (in addition to the core caches that are always forwarded). May be specified more than once to add multiple patterns.
Defaults to an empty list, meaning only evictions of the core caches are forwarded.
event.synchronize : Whether to synchronize stream events. Set to false when not using the SSH stream events. Defaults to true.
index.numStripedLocks : Number of striped locks to use during reindexing of secondary indexes. Defaults to 10
index.synchronize : Whether to synchronize secondary indexes. Set to false when using multi-site on Gerrit replicas that do not have an index, or when using an external service such as ElasticSearch. Defaults to true.
index.synchronizeForced : Whether to synchronize forced index events. E.g. on-line reindex automatically triggered upon version upgrades. Defaults to true.
index.threadPoolSize : Maximum number of threads used to send index events to the target instance. Defaults to 4.
index.maxTries : Maximum number of times the plugin should attempt to reindex changes. Setting this value to 0 will disable retries. After this number of failed tries, an error is logged and the local index should be considered stale and needs to be investigated and manually reindexed.
Defaults to 2.
index.retryInterval : The time interval in milliseconds between subsequent auto-retries. Defaults to 30000 (30 seconds).
broker.indexEventTopic : Name of the topic to use for publishing indexing events Defaults to GERRIT.EVENT.INDEX
broker.streamEventTopic : Name of the topic to use for publishing all stream events. Default: gerrit
broker.cacheEventTopic : Name of the topic to use for publishing cache eviction events Defaults to GERRIT.EVENT.CACHE
broker.projectListEventTopic : Name of the topic to use for publishing cache eviction events Defaults to GERRIT.EVENT.PROJECT.LIST
broker.streamEventPublishTimeoutMs : The timeout in milliseconds for publishing stream events. Defaults to 30000 (30 seconds).
NOTE: All broker settings are ignored when all of the cache, index or event synchronization is disabled.
ref-database.enabled : Enable the use of a shared ref-database Defaults: true
ref-database.replicationLagRefreshInterval : Enable the auto-refresh of the metrics to trace the auto-replication lag by polling on a regular basis. Set to zero for disabling the polling mechanism. Defaults: 60 min
ref-database.enforcementRules.<policy> : Level of consistency enforcement across sites on a project:refs basis. Supports two values for enforcing the policy on multiple projects or refs. If the project or ref is omitted, apply the policy to all projects or all refs.
The <policy> can be one of the following values: 1. REQUIRED - Throw an exception if a git ref-update is processed again a local ref not yet in sync with the shared ref-database. The user transaction is cancelled. The Gerrit GUI (or the Git client) receives an HTTP 500 - Internal Server Error. 2. IGNORED - Ignore any validation against the shared ref-database. *Example:* ``` [ref-database "enforcementRules"] IGNORED = AProject:/refs/heads/feature ``` Ignore the alignment with the shared ref-database for AProject on refs/heads/feature. Defaults: No rules = All projects are REQUIRED to be consistent on all refs.
projects.pattern : Specifies which projects events should be send via broker. It can be provided more than once, and supports three formats: regular expressions, wildcard matching, and single project matching. All three formats match case-sensitive.
Values starting with a caret `^` are treated as regular expressions. For the regular expressions details please follow official [java documentation](https://docs.oracle.com/javase/tutorial/essential/regex/). Please note that regular expressions could also be used with inverse match. Values that are not regular expressions and end in `*` are treated as wildcard matches. Wildcards match projects whose name agrees from the beginning until the trailing `*`. So `foo/b*` would match the projects `foo/b`, `foo/bar`, and `foo/baz`, but neither `foobar`, nor `bar/foo/baz`. Values that are neither regular expressions nor wildcards are treated as single project matches. So `foo/bar` matches only the project `foo/bar`, but no other project. By default, all projects are matched.
replication.push-filter.minWaitBeforeReloadLocalVersionMs : Specifies the minimum amount of time in milliseconds replication plugin filter will wait before retrying check for ref which is not up to date with global-refdb.
By default: 1000 milliseconds
replication.push-filter.maxRandomWaitBeforeReloadLocalVersionMs : Specifies the additional amount of time in milliseconds replication filter will wait before retrying check for ref which is not up to date with global-refdb.
If maxRandomWaitBeforeReloadLocalVersionMs is set to zero random sleep for not in sync refs is disabled. By default: 1000 milliseconds
replication.fetch-filter.minWaitBeforeReloadLocalVersionMs : Specifies the minimum amount of time in milliseconds pull-replication filter wait before retrying check for ref which is not up to date with global-refdb.
By default: 1000 milliseconds
replication.fetch-filter.maxRandomWaitBeforeReloadLocalVersionMs : Specifies the additional amount of time in milliseconds pull-replication filter will wait before retrying check for ref which is not up to date with global-refdb.
If maxRandomWaitBeforeReloadLocalVersionMs is set to zero random sleep for not in sync refs is disabled. By default: 1000 milliseconds
The @PLUGIN@ plugin is also responsible for filtering out replication events that may risk to create a split-brain situation. It integrates the push and pull replication filtering extension points for validating the refs to be replicated and dropping some of them.
Replication plugin
When using the Gerrit core replication plugin, also known as push-replication, link the replication.jar to the $GERRIT_SITE/lib directory and add the following libModule to gerrit.config:
[gerrit] installModule = com.googlesource.gerrit.plugins.replication.ReplicationExtensionPointModule
The above configuration would be automatically detected by the @PLUGIN@ plugin which would then install the PushReplicationFilterModule for filtering outgoing replication refs based on their global-refdb status:
Outgoing replication of refs that are NOT up-to-date with the global-refdb will be discarded, because they may cause split-brain on the remote replication endpoints.
All other refs will be pushed as normal to the remote replication ends.
Pull-replication plugin
When using the pull-replication plugin, link the pull-replication.jar to the $GERRIT_SITE/lib directory and add the following two libModules to gerrit.config:
[gerrit]
installModule = com.googlesource.gerrit.plugins.replication.pull.ReplicationExtensionPointModule
The above configuration would be automatically detected by the @PLUGIN@ plugin which would then install the PullReplicationFilterModule for filtering incoming fetch replication refs based on their global-refdb status.
Incoming replication of refs that locally are already up-to-date with the global-refdb will be discarded, because they would not add anything more to the current status of the local refs.
All other refs will be fetched as normal from the replication sources.