Rebuilding the Sling Launchpad in AEM | AEM Community Blog Seeding

[kautuk_sahni]

Rebuilding the Sling Launchpad in AEM by jetteroheller

Abstract

Sometimes, while running an AEM system, you’ll one into one of a whole host of error conditions which doesn’t seem to have any decent explanation. A few of them are:

1. On restarting AEM, some bundles come up in the “INSTALLED” state, but won’t start properly, automatically.
2. After a deployment, upgrade, service pack release or cumulative fix pack release, AEM fails to start properly on one server, yet it works on another seemingly-identical one.
3. Changing an OSGI configuration in the Felix console doesn’t take effect – you make the change in, say, /system/console/slinglog, but still don’t see the log you just configured.
4. Other random class-loading issues, where on some servers (deployed the same way) all of the bundles start, but on one server it refuses to start at all.

If you’ve tried the usual suspects and still are left scratching your head, one go-to troubleshooting step I’ve taken (quite often in fact) is to rebuild the Launchpad.

How the Launchpad Works with your AEM OSGI Configurations
Adobe Experience Manager is built off of a number of open-source projects, and one of the key components of such is Apache Sling. When you start AEM for the first time, the AEM Quickstart jar file unpacks, and begins its self-configuration to start up. One of those steps is to unpack and create the Sling Launchpad.

When your AEM system starts for the first time, you’ll see log lines that look like this:

12.03.2019 13:19:14.191 *INFO* [FelixStartLevel] org.apache.sling.settings.impl.SlingSettingsServiceImpl Read Sling ID null from file /home/tad/aem/crx-quickstart/launchpad/felix/bundle7/data/sling.id.file
12.03.2019 13:19:14.354 *INFO* [FelixStartLevel] org.apache.sling.launchpad.installer Service [Apache Sling Launchpad Startup Listener,28, [org.apache.sling.installer.api.event.InstallationListener]] ServiceEvent REGISTERED
12.03.2019 13:19:14.357 *INFO* [FelixStartLevel] org.apache.sling.launchpad.installer.impl.LaunchpadConfigInstaller Activating launchpad config installer, configuration path=resources/config, install path=resources/install


12.03.2019 13:19:14.191 *INFO* [FelixStartLevel] org.apache.sling.settings.impl.SlingSettingsServiceImpl Read Sling ID null from file /home/tad/aem/crx-quickstart/launchpad/felix/bundle7/data/sling.id.file
12.03.2019 13:19:14.354 *INFO* [FelixStartLevel] org.apache.sling.launchpad.installer Service [Apache Sling Launchpad Startup Listener,28, [org.apache.sling.installer.api.event.InstallationListener]] ServiceEvent REGISTERED
12.03.2019 13:19:14.357 *INFO* [FelixStartLevel] org.apache.sling.launchpad.installer.impl.LaunchpadConfigInstaller Activating launchpad config installer, configuration path=resources/config, install path=resources/install

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Rebuilding the Sling Launchpad in AEM

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