[MariemBaccari]

This PR partially addresses #1719. It depends on #1907 so only the last commit should be reviewed. It implements the CLI tool which sends cluster membership requests to the admin API.

Example command outputs:

> dss 2 list

aux:
  ID                    URL                     ROLE
  5984584214944223614   http://172.27.1.1:9501  leader
  7039456018058520091   http://172.27.2.1:9502  voter
  13471907039939974409  http://172.27.3.1:9503  voter
  removed IDs: [8441425251619929276]
rid:
  ID                    URL                     ROLE
  10439652153256090285  http://172.27.1.1:9501  leader
  18170893708234001536  http://172.27.2.1:9502  voter
  11084500845428996395  http://172.27.3.1:9503  voter
  removed IDs: [2528209532044653231]
scd:
  ID                    URL                     ROLE
  8150101748507923734   http://172.27.1.1:9501  leader
  11799825069385101662  http://172.27.2.1:9502  voter
  18089004189488093466  http://172.27.3.1:9503  voter

> dss 1 remove --url $(url 4)

aux: removed node 8441425251619929276
rid: removed node 2528209532044653231
scd: removed node 11749186930200284609

> dss 4 node

aux: removed (ID 8441425251619929276, http://172.27.4.1:9504)
rid: removed (ID 2528209532044653231, http://172.27.4.1:9504)
scd: removed (ID 11749186930200284609, http://172.27.4.1:9504)

[the-glu]

the example output / message seems unnatural to read no?

[MariemBaccari]

Could you provide an example of what you have in mind ?

[the-glu]

I added a suggestion bellow, it's mostly to have the two sentences together.

(I also changed it to a full example, but that was not the original scope)

[the-glu]

Open question: should this be only in the docs/website part of the documentation instead?

[MariemBaccari]

I think I'd agree with this for the long term. Do we want to do this for the MVP though ?

[MariemBaccari]

I removed the README.md. It will be addressed separately as part of #1747.

[the-glu]

It calls the admin API served by the core-service of the DSS node on the Unix socket at --admin_socket. A DSS node using the raft datastore runs one Raft group per service: aux, rid and scd. Each group has its own members, and a node joins or leaves each of them independently. A dssctl raft command sends one request per selected group, all groups by default. A change can therefore succeed for some groups and fail for others. In that case, the command can be retried for the failed groups only with --groups.

dssctl raft add --url http://dss4.example.com:9500)

aux: added node 9145876235489012733 (http://dss4.example.com:9500)
scd: added node 3376251980046127518 (http://dss4.example.com:9500)
Error: rid: 503 Service Unavailable: failed to reach the node at http://dss4.example.com:9500 (E:…)

dssctl raft add --url http://dss4.example.com:9500) --groups rid

rid: added node 424242 (http://dss4.example.com:9500)