[chef] Re: Configure server to integer mapping

[Andrew Brown < >]

Hi Bryan,

You could also store the entire cluster configuration in Chef, and pull
out the node’s ID based on the IP address/hostname/etc.

For example:
default['zk']['cluster']['192.168.1.20']['id'] = 1
default['zk']['cluster']['192.168.1.21']['id'] = 2

default['zk']['cluster']['192.168.1.22']['id'] = 3



ip = node['ipaddress']
myid = node['zk']['cluster'][ip]['id']
if myid.nil?
  raise 'Cannot find ME in cluster'
end

template '/etc/zookeeper/conf/myid' do
  variables({ :myid => myid })
end

# Template contents
<%= @myid %>



--
Cheers,
Andrew


On 2014-10-29, 10:50 PM, 
"
 "
 
<
 >
 wrote:

>Hi everyone,
>
>For a few services like zookeeper or kafka, they require a server to
>integer
>mapping like this,
>
>server a - 1
>server b - 2
>...
>
>This is particularly difficult to do in Chef (outside of manually
>configuring
>this) using things like search. Some methods I have tried or seen,
>
> 1. Search for nodes and sort nodes by name. Use the index of each server
>as
>their id. This can cause servers to use the same id for a moment if
>provisioning servers concurrently. This can also cause problems if a new
>node
>doesn't get appended to the end causing a number of servers to change
>their
>ids.
>
> 2. Convert ipaddress or some other attribute into an integer.
>Unfortunately
>this produces an integer too large as services like zookeeper only allow
>ids
>between 0-255.
>
> 3. Set this id on the node during provisioning and track the current id
>somewhere. Then you can use search to just get the mapping.
>
>Does anyone have other suggestions? It seems like 3 is the best option
>though
>not terrible easy to do. It could be easier than I think if I use
>something
>like chef-metal and define each machine with an id.
>
>Bryan