71 lines
3.1 KiB
Plaintext
71 lines
3.1 KiB
Plaintext
[[modules-gateway]]
|
|
== Gateway
|
|
|
|
The gateway module allows one to store the state of the cluster meta
|
|
data across full cluster restarts. The cluster meta data mainly holds
|
|
all the indices created with their respective (index level) settings and
|
|
explicit type mappings.
|
|
|
|
Each time the cluster meta data changes (for example, when an index is
|
|
added or deleted), those changes will be persisted using the gateway.
|
|
When the cluster first starts up, the state will be read from the
|
|
gateway and applied.
|
|
|
|
The gateway set on the node level will automatically control the index
|
|
gateway that will be used. For example, if the `local` gateway is used,
|
|
then automatically, each index created on the node will also use its own
|
|
respective index level `local` gateway. In this case, if an index should
|
|
not persist its state, it should be explicitly set to `none` (which is
|
|
the only other value it can be set to).
|
|
|
|
The default gateway used is the
|
|
<<modules-gateway-local,local>> gateway.
|
|
|
|
[float]
|
|
[[recover-after]]
|
|
=== Recovery After Nodes / Time
|
|
|
|
In many cases, the actual cluster meta data should only be recovered
|
|
after specific nodes have started in the cluster, or a timeout has
|
|
passed. This is handy when restarting the cluster, and each node local
|
|
index storage still exists to be reused and not recovered from the
|
|
gateway (which reduces the time it takes to recover from the gateway).
|
|
|
|
The `gateway.recover_after_nodes` setting (which accepts a number)
|
|
controls after how many data and master eligible nodes within the
|
|
cluster recovery will start. The `gateway.recover_after_data_nodes` and
|
|
`gateway.recover_after_master_nodes` setting work in a similar fashion,
|
|
except they consider only the number of data nodes and only the number
|
|
of master nodes respectively. The `gateway.recover_after_time` setting
|
|
(which accepts a time value) sets the time to wait till recovery happens
|
|
once all `gateway.recover_after...nodes` conditions are met.
|
|
|
|
The `gateway.expected_nodes` allows to set how many data and master
|
|
eligible nodes are expected to be in the cluster, and once met, the
|
|
`gateway.recover_after_time` is ignored and recovery starts.
|
|
Setting `gateway.expected_nodes` also defaults `gateway.recovery_after_time` to `5m` added[1.3.0, before `expected_nodes`
|
|
required `recovery_after_time` to be set]. The `gateway.expected_data_nodes` and `gateway.expected_master_nodes`
|
|
settings are also supported. For example setting:
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
gateway:
|
|
recover_after_time: 5m
|
|
expected_nodes: 2
|
|
--------------------------------------------------
|
|
|
|
In an expected 2 nodes cluster will cause recovery to start 5 minutes
|
|
after the first node is up, but once there are 2 nodes in the cluster,
|
|
recovery will begin immediately (without waiting).
|
|
|
|
Note, once the meta data has been recovered from the gateway (which
|
|
indices to create, mappings and so on), then this setting is no longer
|
|
effective until the next full restart of the cluster.
|
|
|
|
Operations are blocked while the cluster meta data has not been
|
|
recovered in order not to mix with the actual cluster meta data that
|
|
will be recovered once the settings has been reached.
|
|
|
|
include::gateway/local.asciidoc[]
|
|
|