Moving Solaris Container to a different host

Cloning Solaris Container is pretty straight forward. But what if you want to have an identical container on another host? In a nutshell:

  1. Make a clone of an existing container on host A
  2. Detach the clone
  3. Compress it and move it to host B
  4. Create configuration for the moved container
  5. Decompress the container on host B
  6. Attach the decompressed container

I have done this on Solaris 10 8/07. Before going any further, it is important that both host A and host B are running the same release of Solaris and they are both at the same patch level. Otherwise, you will almost certainly run into a situation where the container will refuse to attach to the new host.

I have created a cloned container called mx2. First, I have detached the container:

bash-3.00# zoneadm -z mx2 detach

Then I compressed the container directory so I could move it to host B. It does not really matter which tool you use to compress the directory. Just make sure you preserve permissions, ownership or ACL’s . For me, for some reason tar had a little of an ordeal compressing the container directory:

bash-3.00# cd /export/home/zones  
bash-3.00# tar cf mx2.tar mx2  
tar: mx2/root/usr/jdk/instances/jdk1.5.0/jre/lib/sparc/cpu/sparcv9+vis/sparcv9/ symbolic link too long
tar: mx2/root/usr/jdk/instances/jdk1.5.0/jre/lib/sparc/cpu/sparcv9+vis2/sparcv9/ symbolic link too long

Once I had the directory compressed I scp-ied it to host B. Then I decompressed it in the zones directory:

bash-3.00# cd /export/home/zones  
bash-3.00# tar xf mx2.tar

I have recreated the problematic symlinks mentioned above manually. If you are having trouble attaching the container check that container configurations are the same on both systems.

Before you can attach a container, you need to have container configuration in place. Without it you will not be able to attach the container.

Make sure your configuration is correct. I was attaching full root container and the system was complaining that the container being attached is missing some packages. In reality, my container configuration was for sparse root container. It turned out that when I was importing container configuration, some inherit-package-dir statements were added which has caused attach operation to fail. I had to remove those manually.

So, again, before attaching the container make sure your container configuration is good, you are inheriting correct package directories, etc. Once you have that right, you can attach the new container:

bash-3.00# zoneadm -z mx2 attach

That’s it. Depending on your needs you might want to change hostname, ip address and so on.

Some interesting linkage: Solaris Containers replication