libcluster_ec2 v0.3.0 ClusterEC2.Strategy.Tags View Source
This clustering strategy works by loading all instances that have the given tag associated with them.
All instances must be started with the same app name and have security groups configured to allow inter-node communication.
config :libcluster,
topologies: [
tags_example: [
strategy: Elixir.ClusterEC2.Strategy.Tags,
config: [
ec2_tagname: "mytag",
ec2_tagvalue: "tagvalue"
app_prefix: "app"
ip_type: :private
polling_interval: 10_000]]]
Configuration Options
Key | Required | Description |
---|---|---|
:ec2_tagname | yes | Name of the EC2 instance tag to look for. |
:ec2_tagvalue | no | Can be passed a static value (string), a 0-arity function, or a 1-arity function (which will be passed the value of :ec2_tagname at invocation). |
:app_prefix | no | Will be appended to the node’s private IP address to create the node name. |
:ip_type | no | One of :private or :public, defaults to :private |
:polling_interval | no | Number of milliseconds to wait between polls to the EC2 api. Defaults to 5_000 |
Link to this section Summary
Functions
Returns a specification to start this module under a supervisor
Invoked when the server is started. start_link/3
or start/3
will
block until it returns
Callback implementation for Cluster.Strategy.start_link/1
Link to this section Functions
Returns a specification to start this module under a supervisor.
See Supervisor
.
Invoked when the server is started. start_link/3
or start/3
will
block until it returns.
args
is the argument term (second argument) passed to start_link/3
.
Returning {:ok, state}
will cause start_link/3
to return
{:ok, pid}
and the process to enter its loop.
Returning {:ok, state, timeout}
is similar to {:ok, state}
except handle_info(:timeout, state)
will be called after timeout
milliseconds if no messages are received within the timeout.
Returning {:ok, state, :hibernate}
is similar to
{:ok, state}
except the process is hibernated before entering the loop. See
c:handle_call/3
for more information on hibernation.
Returning :ignore
will cause start_link/3
to return :ignore
and the
process will exit normally without entering the loop or calling c:terminate/2
.
If used when part of a supervision tree the parent supervisor will not fail
to start nor immediately try to restart the GenServer
. The remainder of the
supervision tree will be (re)started and so the GenServer
should not be
required by other processes. It can be started later with
Supervisor.restart_child/2
as the child specification is saved in the parent
supervisor. The main use cases for this are:
- The
GenServer
is disabled by configuration but might be enabled later. - An error occurred and it will be handled by a different mechanism than the
Supervisor
. Likely this approach involves callingSupervisor.restart_child/2
after a delay to attempt a restart.
Returning {:stop, reason}
will cause start_link/3
to return
{:error, reason}
and the process to exit with reason reason
without
entering the loop or calling c:terminate/2
.
Callback implementation for GenServer.init/1
.
Callback implementation for Cluster.Strategy.start_link/1
.