Add Remote CLI on Chassis to simplify connections between supervisor and linecard

[noahsolomon-ms]

What I did

Added commands rexec (remote execute) and rshell (remote shell) to SONiC command line on chassis supervisors. These commands allow you to execute a command through SSH from a supervisor on a linecard (rexec) or to enter the SSH shell for a linecard (rshell).
Additionally, these commands take in linecard names, which are then mapped to linecard IP addresses using the Redis State database.

• The rexec command allows you to execute a command on one (or many) linecards.
  • Arguments:
    • LINECARD_NAMES One or more linecard names. Tab-completion enabled.
  • Options:
    • -c/--command COMMAND (required) The command to execute.
    • -p/--password-file Read password from a file. If not provided, user will be prompted for a password.
  • Example 1: rexec linecard0 linecard1 --command "show interface status"
  • Example 2: `rexec all --command "show ip bgp summary"
• The rshell command allows you to access the linecards shell, similar to ssh.
  • Arguments:
    • LINECARD_NAMES One or more linecard names. Tab-completion enabled.
  • Options:
    • -p/--password-file Read password from a file. If not provided, user will be prompted for a password.
  • Example usage: rshell linecard0

How I did it

I created the rcli directory with multiple files that use Click to parse command line inputs. The two relevant files here are rexec.py and rshell.py. These files also make use of linecard.py, which contains most of the plumbing to initiate and manage SSH connections. This project primarily uses the Paramiko Python library to manage SSH connections.

How to verify it

(work in progress)

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: noahsolomon-ms / name: Noah Solomon (19cd215, b1e6de2, 907e170, 3e531b2, 2e57621, b932d80, 64ea522, e48879a, a443cb2, e6f9501, c439e50, 41e99b8)

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new alerts:

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This pull request introduces 1 alert when merging c1f95ed into 14c483f - view on LGTM.com

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This pull request introduces 1 alert when merging 2755737 into 7704f63 - view on LGTM.com

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