Not able to SSH to KVM guests after installing Docker CE

[rajesh10k (Rajesh C)]

Hi
After installing Doceker CE , am not able to SSH into KVM guests from other computers in LAN, but am able to SSH from KVM host to guests.

Note: KVM host is usin bridge network over wired LAN

How to solve this issue

[ilikelinux (L.S.)]

Welcome to ask.fedora @rajesh10k

@rajesh10k

Note: KVM host is usin bridge network over wired LAN

How did you do this?

I had a similar problem … se the discussion where I started:

Virtual Machine Manager | Bridged Network | Why so complicated to achiev?

If you want to bridge the physical network to the VM, you first have to create the bridge in NetworkManager and add the physical NIC as a port of the bridge. In this example, I’m bridging eth0 to a new bridge br0: # nmcli con add con-name br0 ifname br0 type bridge autoconnect yes ipv4.method auto ipv6.method auto # nmcli con add con-name br0-port ifname eth0 type ethernet slave-type bridge master br0 autoconnect yes Note that your existing connection for the ethernet interface will have to b…

[rajesh10k (Rajesh C)]

Hi ilikelinux

Thanks for the replay , I’ve gone through the link , what I understood is you created a NAT network, (but are you able to SSH to VM ? ).

In my scnerio I created bridged network and able to SSH and internet in VM’s, but after installing Docker-CE, I am able to use internet only in Docker containers,
but not in KVM VM’s, and also not able to SSH to KVM VM’s.

What I understand is that its a routing issue, but not able to fix it.

Regards
Rajesh

[ilikelinux (L.S.)]

@rajesh10k

what I understood is you created a NAT network, (but are you able to SSH to VM ? ).

In Virtual Machine Manager > Edit > Connection Details > Virtual Networks, remove all networks.

Afterwards check the two points @glb mentions in the topic below.

Br0 suddenly stopped passing traffic

Yeah. There are some non-trivial forwarding rules being created by the tools there. Unfortunately, I’m not familiar enough with that sort of setup to be of much help. A few basic things to check though would be: Use brctl show to make sure that the right network interfaces are actually on the right bridges. Since you said this is using libvirt, make sure that there is a allow br0 line (or whatever your bridge name is) in /etc/qemu/bridge.conf. If none of that works, I’d probably be down to tr…

When this done, do select the network on the specific VM as in the picture below:

Now you can start the VM

With this procedure you theoretically created you a virtual x-port switch where you connect all your VM’s.

If you use Fedora Workstation please do you the favor and use the nm-connection-editor instead of the build in Network editor in the Settings of Gnome 4.2x. Otherwise you will get bothered wit auto network etc … really annoying.

Of course, if you are a happy Terminal user make use of nmcli to manage your network.

@rajesh10k

Docker-CE, I am able to use internet only in Docker containers,
but not in KVM VM’s, and also not able to SSH to KVM VM’s.

If you can, try to include toolbox or ‘podman’ with rootless containers, in your workflow.
I think this way you not have to fight wit this unnecessary routing troubles.

I will add this mini tutorial to the discussion on discussion.fp.org. Might be that I will get some more Tricks/Tips to tweak the libvirt/network workflow.

Good luck

[rajesh10k (Rajesh C)]

@ilikelinux

After everything am not able to perfectly configure the KVM alongside with Docker,
But I took your advice and included podman, apart form missing “PORTAINER” everything works perfectly in my network.

If you can suggests somthing like portainer for podman, that wolud be great.

Thanks

[ilikelinux (L.S.)]

@rajesh10k

If you can suggests somthing like portainer for podman, that wolud be great.

Unfortunately i can’t. But you can make a new topic and describe what you expect from a app like Portainer. Important is that you give enough info’s what you want to achieve and in what an environment you work.