[LU-17205] Prefix each lctl get_param output line with -H

Related — Fri, 17 Nov 2023 00:48:43 +0000

Add a new '-H' option to 'lctl get_param' that will prefix each output line with the parameter name instead of only the first line by default.

That makes grepping lctl get_param with wildcards much easier as you can now easily now which parameter returns which value:

$ lctl get_param -H osc.*.state | grep current
osc.lustre-OST0000-osc-ff1148c0.state=current_state: FULL
osc.lustre-OST0001-osc-ff1248c0.state=current_state: DISCONN
osc.lustre-OST0002-osc-ff1348c0.state=current_state: FULL
osc.lustre-OST0003-osc-ff1448c0.state=current_state: FULL
osc.lustre-OST0004-osc-ff1548c0.state=current_state: FULL

It could be combined with clubak from ClusterShell by example, to compare connection tunings, ie:

# lctl get_param -H osc.*.srpc_info | grep -v id: | clubak -bS=
---------------
osc.lustre-OST[0002-0009]-osc-ff1348a7.srpc_info (8)
---------------
rpc flavor:     krb5n
bulk flavor:    krb5n
flags:          rootonly,bulk,
refcount:       3
nctx:   1
gc internal     3600
gc next 3459
---------------
osc.lustre-OST[0000-0001]-osc-ff1348a7.srpc_info (2)
---------------
rpc flavor:     null
bulk flavor:    null
flags:          -,
refcount:       416
nctx:   1
gc internal     0
gc next 0

It could also be useful even with 1 line of output as it does not force a line feed if the value is larger than 80 chars.

It also prints an output line even for empty values. That also makes life easier for admins.

Open to use another option name if you prefer.

Whamcloud Community JIRA

[LU-17205] Prefix each lctl get_param output line with -H