scripts/h0: Add `hosts' command

[1468ca0b-2a64-4fb4-8e52-ea5806644b4c]

Created by: vvv

• Add hosts command. Usage examples:

  $ M0_CLUSTER= h0 hosts
  $
  $ M0_CLUSTER=cluster.yaml h0 hosts
  client1.local,ssu1.local,ssu2.local,cmu.local
  $
  $ pdsh -w $(M0_CLUSTER=cluster.yaml h0 hosts) true
  $

• Prelink more executables.

[1468ca0b-2a64-4fb4-8e52-ea5806644b4c]

Created by: andriytk

Show comma-separated list of cluster nodes

Well... :)

[1468ca0b-2a64-4fb4-8e52-ea5806644b4c]

Created by: vvv

The primary motive for adding h0 hosts was to simplify pdsh calls.

pdsh -w $(h0 hosts) ...  # assuming ~/.m0-cluster.yaml exists

(I thought about adding h0 pdsh, but decided not to go that far.)

[1468ca0b-2a64-4fb4-8e52-ea5806644b4c]

Created by: vvv

I mean, ugh!

😃

[1468ca0b-2a64-4fb4-8e52-ea5806644b4c]

Created by: vvv

The word “hosts” is used everywhere else in this script (as well as in ssh(1) and pdsh(1)).

[1468ca0b-2a64-4fb4-8e52-ea5806644b4c]

Created by: vvv

No, thanks. :)

[1468ca0b-2a64-4fb4-8e52-ea5806644b4c]

Created by: andriytk

Why not nodes?

[1468ca0b-2a64-4fb4-8e52-ea5806644b4c]

Created by: chumakd

alternative formatting:

    for exe in dix/utils/m0dixinit \
               mero/m0d \
               utils/mkfs/m0mkfs \
               utils/trace/m0traced \
               utils/trace/m0tracedump
    do
        $M0_SRC_DIR/$exe -h &>/dev/null || true
    done