I am trying to sync data between an Ubuntu instance and a CentOS 7 instance. It's like a bi-directional rsync so I thought unison would be the best tool. I installed it on both instances but when I tried to connect them I received an error because the versions are different:
unison -testServer . ssh://myuser@myremotehost/efs/home/ Contacting server... myuser@myremotehost's password: Fatal error: Received unexpected header from the server: expected "Unison 2.48\n" but received "Unison 2.40\n\000\000\000\000\017", which differs at "Unison 2.40". This can happen because you have different versions of Unison installed on the client and server machines, or because your connection is failing and somebody is printing an error message, or because your remote login shell is printing something itself before starting Unison.
So I tried to make the versions match but when I look I only see the one version available on Ubuntu.
myuser@mylocalhost:/nas/$ apt policy unison unison: Installed: 2.48.4-1ubuntu1 Candidate: 2.48.4-1ubuntu1 Version table: *** 2.48.4-1ubuntu1 500 500 http://us.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages 100 /var/lib/dpkg/status
And when I look on CentOS 7 I don't see any versions
$ yum --showduplicates list unison Loaded plugins: fastestmirror, langpacks Loading mirror speeds from cached hostfile * base: d36uatko69830t.cloudfront.net * epel: mirror.prgmr.com * extras: d36uatko69830t.cloudfront.net * updates: d36uatko69830t.cloudfront.net Error: No matching Packages to list
However, I can install it with no problem:
$ sudo yum install unison Loaded plugins: fastestmirror, langpacks Loading mirror speeds from cached hostfile * base: d36uatko69830t.cloudfront.net * epel: d2lzkl7pfhq30w.cloudfront.net * extras: d36uatko69830t.cloudfront.net * updates: d36uatko69830t.cloudfront.net Package unison240-gtk-2.40.128-5.el7.x86_64 already installed and latest version Nothing to do
Am I doing something wrong with finding the versions? How can I make them match?
The local host is:
myuser@mylocalhost:/nas$ cat /etc/*release DISTRIB_ID=Ubuntu DISTRIB_RELEASE=18.04
The remote host is:
$ cat /etc/*release CentOS Linux release 7.6.1810 (Core)