Docker Swarm and Portainer

[Jens-Wymeersch]

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Hello,

I used the following tutorial https://www.youtube.com/watch?v=nmas_zbcMeU
3 ubuntu servers (v24.04)
for the virtual IP - keepalived
for replicated storage - microceph - replicated storage is residing on /mnt/cephfs/
Both work perfectly and tested.

Dockerswarm looks like

ID                            HOSTNAME       STATUS    AVAILABILITY   MANAGER STATUS   ENGINE VERSION
ID1 *                       dockerswarm1   Ready           Active         Leader                        27.3.1
ID2                         dockerswarm2   Ready           Active         Reachable                     27.3.1
ID3                         dockerswarm3   Ready           Active         Reachable                     27.3.1

The purpose is to have an HA and load balanced environment for my docker containers.

All my nodes are manager nodes. Based on the documentation, https://portal.portainer.io/knowledge/how-can-i-ensure-portainers-configuration-is-retained, I need to restrict the portainer server to one node.
So if this node goes down, I won't be able to access portainer till it gets up again. Correct ?
If I am correct, I have 2 options

1. Follow the documentation amd make the node running the portainer server high available on the proxmox side
2. install the portainer server on a dedicated proxmox vm which i make high available. How would this be done ?
   Other options or comments ?

[Nick-Portainer]

Hello! That’s correct. If the node running Portainer goes down, you’ll lose access to Portainer as well. We typically recommend, if possible, running the Portainer server outside of your swarm on a dedicated Docker standalone host and connecting the swarm via an agent. If you decide to keep Portainer within the swarm, ensure that, in the event it goes down, another node can access the Portainer data—usually through a network share. However, please note that storing Portainer’s data on a network share can have issues as databases and network shares can be hit and miss

[Jens-Wymeersch]

@Nick-Portainer Just to be certain
I would use the following ?

• use the following for the standalone machine https://docs.portainer.io/start/install/server/docker/linux
• use the following to install the agent on the swarm https://docs.portainer.io/2.17/start/agent/swarm/linux

Based on what I've read, I only need to install the agent once. Is this correct ? If so, I assume that when the node goes down, the agent will move to another node. Correct ?

[Jens-Wymeersch]

@Nick-Portainer So the installation with a portainer server outside the swarm works but results in 4 nodes - license issue

[Nick-Portainer]

Yes this is correct, each node in a Swarm will go against your node license count as well as Portainer itself.

[Jens-Wymeersch]

@Nick-Portainer So what is the point of having a "free" license if you can't use it ?

[Nick-Portainer]

You can use it with a limit on the number of nodes. If you wish to use more than the 3 free nodes, consider purchasing a Home and Student license for personal use as a recommendation moving forward.