collaboration and communication sw opensource


New Member
Hello everybody,
I received a request for the installation of a software like Slack, but opensource, free, and above all installable on premise. (I will use Docker)
Indispensable requirement: the platform must be integrated with GitLabCE currently in production. After doing some research, I am to choose one of Mattermost, RocketChat and Zulip, among the most complete (I'm thinking...)
The user base now is not more than 50, so I wouldn't want to use oversized software and therefore the huge resources required.
Has anyone already had a similar request and what did you choose?

Thanks for the opinion,
Best regards


Active Member
This is not a one size for all question.
Do you need an entire OS on every VM? Or are you trying to isolate software processes?

docker is being replaced by podman on many newer distros. The main difference is
there is no kernel in a podman VM.

What are you using gitlab for? Source control of the VM's themselves, or source control for the software on the VM's? Are you using CICD?

If you want a "small footprint" Linux to run.. it seems most docker shops use Alpine linux.
If you want to lot of docker/podman tools to make life easier, you might want to run on fedora.

If you really need a full-blown OS on your VM's, you might want to run libvirt QEMU, KVM with gnome boxes, or virtualBox. (You will need pretty hefty hardware if you have a lot of VM's).


New Member
Ok, I probably set the question wrong.
I need a messaging platform like Slack and I would like to choose one of the three previously mentioned. Which of these is suitable for a low number of users? For example, at most 20 developers?

At the moment it is used for some Bitbucket, others use SVN Tortoise, other TFS: the company project will be to migrate everything and everyone on the GitLab-CE solution, on premise. It is used both for Visual Studio and for the ETL in Penthao production (jobs and transformations)


Active Member
Sorry... I thought you meant slack linux.

I have not setup a messaging server since the IRC days, but I hear and XMPP are good.

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