Migration

When Meshploy is installed beside another platform on the same server, setup can plan a migration: moving that platform’s apps and databases onto Meshploy without a big switch-over. Only the workspace owner sees it.

Every step runs on the server itself, through the host agent on the gateway. The console queues the request, and the step’s progress arrives on the page as it runs. If the host agent is not reporting, nothing runs; the page says how to start it.

The steps

Prepare builds the Meshploy side of the plan with everything stopped and every route paused. It touches nothing of the old platform’s, and can be run again.
Move each group when you are ready. A group is what must move together so its data never lives in two places: a database with every app that uses it. Moving one stops the old copies, brings the new ones up with their data, and switches the group’s domains.
Cut over hands the web ports to Meshploy: it carries the certificates across, stops the old edge, and starts Meshploy’s on 80 and 443. Expect a few seconds of refused connections. Every group that can move must have moved first, unless you take the edge first.
Finish removes what is left of the old platform.

Undoing

Until Finish, everything can be put back. Roll back a single group, or Put everything back, which returns every group to the old platform and gives it back the ports. Data written into Meshploy since a group moved stays in Meshploy.

Finish cannot be undone. By default it leaves the old platform’s volumes on the disk, holding their data; tick Remove its volumes too only when you are sure nothing on them is needed.

Compose apps

A compose app becomes a stack. The plan reads its compose file first and says what will happen to each service: built ones move on the image they run now and build from their Dockerfile on the next deploy, one-shot steps run once per deploy, repository files and published addresses come across. A service that reaches into the machine itself, with host networking, privileges, devices, the Docker socket or a folder of the host, asks before the app moves: move it without that, or leave the app on the old platform.

What the app looked like from outside stays as it was. A port published on every address opens on the gateway at the same number, one published on 127.0.0.1 stays on the gateway’s loopback, and one on a single address stays on that address. Each service keeps the memory and CPU its container had, which for most means the whole machine, shown on the service to be tightened when you choose. Services start in the order compose started them, a one-shot step finishing before what waits for it.

A compose app kept in git reads its file and its repository files from the old platform’s checkout until its git provider is reconnected here, so it moves before that. Its images are carried while it still serves, so its downtime is the data copy and the start.

Taking the edge first

To run both platforms side by side for a while, take the edge before the groups move. Meshploy’s edge starts on 80 and 443, and the old edge moves to a port of its own on the same machine and keeps serving every domain that has not moved: Meshploy hands those hostnames on to it, and forwards who the visitor was. Groups then move one at a time, and moving one only switches its domains.

The old platform keeps running and redeploying what it already serves. A domain added there after the edge was taken is not reached, since Meshploy only hands on the hostnames it knew at that moment, so new work belongs on Meshploy. Finish waits until every group that can move has. Put everything back gives the old edge its ports again.

Groups that cannot move

A group Meshploy cannot move keeps running on the old platform. At cut over it loses its domains, because the ports change hands; the console says which domains before you confirm. Finish leaves it running.

Terms

Group: What must move together so its data never lives in two places: a database with every app that uses it. More
Cut over: Hands ports 80 and 443 to Meshploy, with the certificates. Every group that can move must have moved first, unless the edge is taken first. More
Take the edge first: Cut over while groups are still to move. The old edge keeps serving them from a port of its own until they do. More
Finish: Removes what is left of the old platform. The one step that cannot be undone. More