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diff --git a/content/documentation/reference_manual/layout.md b/content/documentation/reference_manual/layout.md deleted file mode 100644 index 3d325c7..0000000 --- a/content/documentation/reference_manual/layout.md +++ /dev/null @@ -1,79 +0,0 @@ -+++ -title="Doc Post" -date=2018-08-20 -+++ - -# Creating and updating a cluster layout - -The cluster layout in Garage is a table that assigns to each node a role in -the cluster. The role of a node in Garage can either be a storage node with -a certain capacity, or a gateway node that does not store data and is only -used as an API entry point for faster cluster access. -An introduction to building cluster layouts can be found in the [production deployment](/cookbook/real_world.md) page. - -## How cluster layouts work in Garage - -In Garage, a cluster layout is composed of the following components: - -- a table of roles assigned to nodes -- a version number - -Garage nodes will always use the cluster layout with the highest version number. - -Garage nodes also maintain and synchronize between them a set of proposed role -changes that haven't yet been applied. These changes will be applied (or -canceled) in the next version of the layout - -The following commands insert modifications to the set of proposed role changes -for the next layout version (but they do not create the new layout immediately): - -```bash -garage layout assign [...] -garage layout remove [...] -``` - -The following command can be used to inspect the layout that is currently set in the cluster -and the changes proposed for the next layout version, if any: - -```bash -garage layout show -``` - -The following commands create a new layout with the specified version number, -that either takes into account the proposed changes or cancels them: - -```bash -garage layout apply --version <new_version_number> -garage layout revert --version <new_version_number> -``` - -The version number of the new layout to create must be 1 + the version number -of the previous layout that existed in the cluster. The `apply` and `revert` -commands will fail otherwise. - -## Warnings about Garage cluster layout management - -**Warning: never make several calls to `garage layout apply` or `garage layout -revert` with the same value of the `--version` flag. Doing so can lead to the -creation of several different layouts with the same version number, in which -case your Garage cluster will become inconsistent until fixed.** If a call to -`garage layout apply` or `garage layout revert` has failed and `garage layout -show` indicates that a new layout with the given version number has not been -set in the cluster, then it is fine to call the command again with the same -version number. - -If you are using the `garage` CLI by typing individual commands in your -shell, you shouldn't have much issues as long as you run commands one after -the other and take care of checking the output of `garage layout show` -before applying any changes. - -If you are using the `garage` CLI to script layout changes, follow the following recommendations: - -- Make all of your `garage` CLI calls to the same RPC host. Do not use the - `garage` CLI to connect to individual nodes to send them each a piece of the - layout changes you are making, as the changes propagate asynchronously - between nodes and might not all be taken into account at the time when the - new layout is applied. - -- **Only call `garage layout apply` once**, and call it **strictly after** all - of the `layout assign` and `layout remove` commands have returned. |