How to migrate from Nexus Professional to Nexus OSS

Question

I want to "downgrade" an installation of Nexus Professional 2.x to Nexus OSS 2.x. Is it possible? What do I have to do?

Answer 1

I just ran into the expired PRO license scenario, and unfortunately I was unable to turn off the PRO realms (User Token, specifically) that were active.

Luckily, Nexus3 exposes a REST API that can be used for that purpose, and after following Sonatype's instructions to boot back into OSS mode, I was able to use one of those APIs to disable the PRO-only realms that I had enabled. Otherwise the Realms page wouldn't load.

The API page is at

${YOUR_NEXUS_URL}/#admin/system/api

And there you can just search in the page for the realm-related (or other) APIs.

Hopefully you'll find this useful ...

Answer 2

Here is Sonatype instruction to downgrade Nexus 3 Pro to Nexus 3 OSS: https://support.sonatype.com/hc/en-us/articles/115015608967-How-to-downgrade-from-Nexus-3-Pro-to-Nexus-3-OSS

Answer 3

The accepted answer to this question is old and doesn't work for the current version (Feb 2021 v3.29) of the Nexus.

Here are few things that I would like to add. These are crucial and essential for the Nexus OSS to work.

1. Make sure that you are downloading the OSS

2. If you just copy the configurations and point to the blobs it doesn't work. You need to take a backup of OrientDB of Nexus and restore it, then only blobs and repositories will be recognized by the Nexus.

Without OrientDB, blobs mean nothing to the Nexus. I will add detailed steps to this answer when I will get some more time. I just put the important points in brief to unblock people who may be stuck just like I was.

Answer 4

As a note: If your license to Nexus 3 Pro has expired, when you log in to the UI, you cannot access anything in the admin UI. You are only redirected back to the License screen with a stern warning message that you don't have a valid license.

I tried removing all Pro plugins etc as in the earlier answer. Tried finding where the Pro licenser was stored on file - but could not find any documentation from Sonatype of this. I assumed it was stored somewhere in the database.

In my case I worked with an evaluation server, so I removed the whole sonatype-work/nexus3 directory and restarted the nexus server. Even without data, it still claimed to be a Nexus Pro installation.

Finally I found the setting stored in the users home directory, in ~/.java/.userPrefs/com/sonatype of all places.

When that directory was removed/renamed I could start Nexus as a regular OSS.

It's not easy to find this in Sonatypes documentation, but they mention it in some places like: https://support.sonatype.com/hc/en-us/articles/213465018-Every-time-Nexus-is-restarted-it-asks-for-the-license-to-be-installed-

Answer 5

Yes, it is not a complicated task.

Install Nexus OSS on the same server. Do change the following so that the new Nexus OSS has the same configuration as the existing Nexus Professional runtime.

Configuration

• port is set in [runtime]/conf/nexus.properties
• sonatype-work directory location is set in [runtime]/conf/nexus.properties
• the java command is set in [runtime]/bin/jsw/conf/wrapper.conf
• the log directory location is set in [runtime]/conf/nexus.properties

Process

• Stop the Professional
• Make sure to backup the sonatype-work/nexus/conf directory
• Remove the professional plugins from sonatype-work/nexus/plugin-repository
• Add the p2 plugins for OSS to the sonatype-work/nexus/plugin-repository sonatype-work/nexus/conf/nexus.xml
• Remove procurement repositories references from nexus.xml
• Remove Scheduled task that use the professional plugins or features from from nexus.xml Note: Those two tasks could have been done from the Nexus Professional UI before stopping it.
• Remove User-Token-Realm from the sonatype-work/nexus/conf/security-configuration.xml

Start the Nexus OSS

• start preferably with nexus console instead of nexus start, so it shows more information
• check the [runtime]/logs/wrapper.log
• check the sonatype-work-nexus/logs/nexus.log