vstart: make -k with optional mon_num (part 2)

[tchaikov]

vstart: use default CEPH_NUM_* if awk fails

see #8251

[tchaikov]

@dillaman could you help take a look? thanks!

[dillaman]

Can you just do something like: CEPH_NUM_MON=awk -F= '/CEPH_NUM_MON/{print $2}' $conf_fn before line 79? If the awk fails, it will fall back to the defaults.

[tchaikov]

if we go this way, we will always continue with whatever CEPH_NUM_{MON,OSD,MDS,RGW} the last vstart run used, even if "-k" is not passed in. in other words,

$ MON=1 OSD=1 MDS=0 ./vstart.sh
$ ./stop
$ MON=1 OSD=2 MDS=0 ./vstart.sh
# what? we have only 1 OSD?

if we move these lines after line 91, we overwrite the options for a non "-k" vstart cluster.

[dillaman]

Fair enough.

[trociny]

This comment is rather for the initial PR (part 1) and can be freely ignored... Anyway, I don't not like very much when sed/awk/... is used to extract values from files like this (that can be parsed by a specialized parser). E.g. the current awk parsing will break when ceph.conf happens to include CEPH_NUM_MON word more than one time.

Instead, we could add e.g. "client.vstart.sh" section to the generated ceph.conf:

[client.vstart.sh]
  ceph num mon = 5
  ...

And parse it using ceph-conf:

MON=`ceph-conf -c $conf_fn --name client.vstart.sh ceph_num_mon`

[tchaikov]

@trociny thanks for the suggestion! i will update this PR later on.

[tchaikov]

changelog

• store the number of {osd,mon,mds,rgw} as settings in the section of "[client.vstart.sh]"
• read the remembered using ceph-conf instead of parsing the ceph.conf using awk.

hope this is okay to introduce the dependency on ceph-conf. but guess we don't use "-k" in our testing, so it's relatively safe.

[dillaman]

My only comment is that perhaps given the distance between usages of "client.vstart.sh", should it use an environment variable "constant"?

[tchaikov]

changelog

• use a variable for "client.vstart.sh" instead of hardwiring it to "client.vstart.sh" at two separated places

[tchaikov]

@dillaman ping?

[dillaman]

Super minor: s/can not/cannot/g

[tchaikov]

changelog

• s/can not/cannot/

@dillaman thanks for the review, fixed and repushed.

[tchaikov]

@dillaman ping?