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I have 4 Rancher servers: one for each environment: dev, sandbox, staging & prod.

3 of them are of an older Rancher 1.4 version (sandbox, staging, prod) & are hosted on OVH hosting, the one left (dev) is on thr latest 1.6.14 & AWS.

I need to move 3 hosts from OVH to AWS & attach all of them to the only one aws Rancher server which already has 1 dev host.

If I stop rancher-agent on one of OVH rancher hosts & reconfigure it to point to aws, then it appears there in the console, but the config for stacks & etc is lost, as it’s, probably, stored in mysql of the original rancher server.

If I deploy a host from each of the OVH rancher servers to AWS, then I’m stuck with the same problem, after I switch the new hosts agents to the only aws rancher server the configurations for stacks & etc will be lost.

Please advise on the strategy to merge all that into single aws rancher server + 4 hosts: one for each environment. I’m trying not to recreate all 3 environments on aws manually, to avoid downtime & a lot of manual work.

Thanks!

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First of all you need to support HA mode. You will need:

  1. external MySQL DB (e.g. AWS RDS Aurora)
  2. external load balancer (e.g. AWS ELB)
  3. 2 additional Rancher Server Nodes (to support quorum of 3)

Once you will be ready with external DB Rancher would ask you to backup & restore his database in it. After that you'll be asked to redeploy Rancher Server with additional params for external DB connection. Then you'll be able to run two more Rancher Server Nodes (e.g. using AWS ELB).

When previous steps have finished you would be able to add more Rancher Agent Nodes in AWS directly from Rancher Hosts tab. After that you can just switch off OVH nodes - payload would be transferred to AWS automagically.

Make sure to backup & restore all databases or data-sensitive instances on OVH hosts.

More information such as HA Requirements etc. can be found in documentation.

  • Yes, HA is the path I'm goint to, but I didn't quite get how the info about configuration of stacks & etc will get from OVH Rancher servers into the AWS Rancher server. I can just stop & run an agent container on an OVH host with parameters to connect to AWS Rancher server, but the info on stacks & etc will be missing. I was thinking that I'll maybe have to dump certain mysql tables from OVH Rancher mysql servers & then import them to AWS Rancher server? – GTXBxaKgCANmT9D9 Jan 17 '18 at 13:43
  • @ValeriiVainkop this depends on the type of Orchestration framework. But all of them would detect that host is failed and will try to restore the load on available resources. As part of HA switch you would have to backup MySQL DB from OVH server and restore it somewhere in AWS RDS (or any other HA database service). – Maksim Jan 17 '18 at 17:26
  • @ValeriiVainkop in HA mode all Rancher Server Nodes would share Database where current stack info is stored. So every node would be aware of overall structure of every environment. – Maksim Jan 17 '18 at 17:29
  • Orchestration framework is Cattle on all Rancher servers. The problem is that I have 4 different Rancher servers with 4 separate mysql databases.I did the following: stopped Rancher server & agent containers on OVH server. Started new agent container with parameters to connect to AWS Rancher server (taken from AWS's Infrastructure->Hosts->Add->Custom).And I saw a new host in AWS Rancher server UI->Hosts but it didn't have any Stack configs as they're stored in mysql on OVH. Of course Rancher server would know about configs if it stored it in one mysql, but I have a different situation. – GTXBxaKgCANmT9D9 Jan 17 '18 at 18:29
  • That's why you need to switch to HA first. Do you have one Rancher server and multiple Hosts in it? Or separate Rancher servers? Independent. Nobody knows others. – Maksim Jan 17 '18 at 18:40

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