gharris1727 commented on code in PR #14068: URL: https://github.com/apache/kafka/pull/14068#discussion_r1283603349
########## docs/connect.html: ########## @@ -543,6 +543,67 @@ <h6>ACL requirements</h6> </tbody> </table> + <h4><a id="connect_plugindiscovery" href="#connect_plugindiscovery">Plugin Discovery</a></h4> + + <p>Plugin discovery is the name for the strategy which the Connect worker uses to find plugin classes and make them accessible to configure and run in Connectors and Tasks. This is controlled by the <a href="#connectconfigs_plugin.discovery"><code>plugin.discovery</code> worker configuration</a>, and has a significant impact on worker startup time. <code>SERVICE_LOAD</code> is the fastest strategy, but care should be taken to verify that plugins are compatible before setting this configuration to <code>SERVICE_LOAD</code>.</p> + + <p>Prior to version 3.6, this strategy was not configurable, and behaved like the <code>ONLY_SCAN</code> mode which is compatible with all plugins. For version 3.6 and later, this mode defaults to <code>HYBRID_WARN</code> which is also compatible with all plugins, but logs a warning for all plugins which are incompatible with the other modes. For unit-test environments that use the <code>EmbeddedConnectCluster</code> this defaults to the <code>HYBRID_FAIL</code> strategy, which stops the worker with an error if an incompatible plugin is detected. Finally, the <code>SERVICE_LOAD</code> strategy will silently hide incompatible plugins and make them unusable.</p> + + <h5><a id="connect_plugindiscovery_compatibility" href="#connect_plugindiscovery_compatibility">Verifying Plugin Compatibility</a></h5> + + <p>To verify if all of your plugins are compatible, first ensure that you are using version 3.6 or later of the Connect runtime. You can then perform one of the following checks:</p> + + <ul> + <li>Start your worker with the default <code>HYBRID_WARN</code>strategy, and WARN logs enabled for the <code>org.apache.kafka.connect</code> package. At least one WARN log message mentioning the <code>plugin.discovery</code> configuration should be printed. This log message will explicitly say that all plugins are compatible, or list the incompatible plugins.</li> + <li>Start your worker in a test environment with <code>HYBRID_FAIL</code>. If all plugins are compatible, startup will succeed. If at least one plugin is not compatible the worker will fail to start up, and all incompatible plugins will be listed in the exception.</li> + </ul> + + <p>If the verification step succeeds, then your current set of installed plugins are compatible, and it should be safe to change the <code>plugin.discovery</code> configuration to <code>SERVICE_LOAD</code>. If you change the set of already-installed plugins, they may no longer be compatible, and you should repeat the above verification. If the verification fails, you must address the incompatible plugins before using the <code>SERVICE_LOAD</code> strategy.</p> + + <h5><a id="connect_plugindiscovery_migrateartifact" href="#connect_plugindiscovery_migrateartifact">Operators: Artifact Migration</a></h5> + + <p>As an operator of Connect, if you discover incompatible plugins, there are multiple ways to try to resolve the incompatibility. They are listed below from most to least preferable.</p> + + <ol> + <li>Upgrade your incompatible plugins to the latest release version from your plugin provider.</li> + <li>Contact your plugin provider and request that they migrate the plugin to be compatible, following the <a href="#connect_plugindiscovery_migratesource">source migration instructions</a>, and then upgrade to the migrated version.</li> + <li>Migrate the plugin artifacts yourself using the included migration script.</li> + </ol> + + <p>The migration script is located in <code>bin/connect-plugin-path.sh</code> and <code>bin\windows\connect-plugin-path.bat</code> of your Kafka installation. The script can migrate incompatible plugin artifacts already installed on your Connect worker's <code>plugin.path</code> by adding or modifying JAR or resource files. This is not suitable for environments using code-signing, as this may change the artifacts such that they will fail signature verification. View the built-in help with <code>--help</code>.</p> + + <p>To perform a migration, first use the <code>list</code> subcommand to get an overview of the plugins available to the script. You must tell the script where to find plugins, which can be done with the repeatable <code>--worker-config</code>, <code>--plugin-path</code>, and <code>--plugin-location</code> arguments. The script will only migrate plugins present in the paths specified, so if you add plugins to your worker's classpath, then you will need to specify those plugins via one or more <code>--plugin-location</code> arguments.</p> + + <p>Once you see that all incompatible plugins are included in the listing, you can proceed to dry-run the migration with <code>sync-manifests --dry-run</code>. This will perform all parts of the migration, except for writing the results of the migration to disk. Note that the <code>sync-manifests</code> command requires all specified paths to be writable, and may alter the contents of the directories. Make a backup of the specified paths, or copy them to a writable directory.</p> Review Comment: It covers the case where `--worker-config` doesn't cover everything. I was imagining this workflow: 1. Operator receives a list of incompatible plugins from an error message or warning in production 2. Operator gets a dev environment and runs `bin/connect-plugin-path.sh list --worker-config config/connect-distributed.properties` and sees a listing 3. Operator verifies that every plugin in the error listing is in the `list` output. 4. If a plugin is missing, the operator figures out where that is coming from (e.g. from the classpath) 5. Operator adds `--plugin-location` arguments and repeats step 3-5 until all plugins are present 6. Operator moves on to `sync-manifests --dry-run`. If I change this to `If incompatible plugins are shown` then the sync-manifests may be incomplete, and the verification steps may fail. I guess since they should do that verification anyway, having them cross-check the errors and list output is a bit redundant. WDYT? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: jira-unsubscr...@kafka.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org