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disk_Check: Scan & mount as RW when disk turns into Read-only#1872

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abdosi merged 5 commits intosonic-net:201911from
renukamanavalan:disk_check_201911
Nov 20, 2021
Merged

disk_Check: Scan & mount as RW when disk turns into Read-only#1872
abdosi merged 5 commits intosonic-net:201911from
renukamanavalan:disk_check_201911

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What I did

How I did it

Cherry pick: PRs #1569, #1736 and #1747

How to verify it

Previous command output (if the output of a command-line utility has changed)

New command output (if the output of a command-line utility has changed)

What I did
There is a bug that occasionally turn root-overlay as RO. This makes /etc & /home as RO. This blocks any new remote user login, as that needs to write into /etc & /home.

This tool scans /etc & /home (or given dirs) as in RW or RO state. If RO, it could create a writable overlay using tmpfs.
This is transient and stays until next reboot. Any write after the overlay will be lost upon reboot.

But this allows new remote users login.

How I did it
Create upper & work dirs in /run/mount (tmpfs). Mount /etc & /home as lowerdirs and use the same name for final merge. This allows anyone opening a file in /etc or /home to operate on the merged overlay, transparently.

How to verify it
Mount any dir on tmpfs ( mount -t tmpfs tmpfs test_dir)
remount as RO (mount -o remount,ro test_dir)
Pass that dir to this script. (disk_check.py -d ./test_dir)
Now it should be RW
1) Set default loglevel to SYSLOG_ERR
2) Make log level configurable via args
…1747)

What I did
Have independent subdirs for each mounted dir to avoid any collisions of files/dirs by same name.
Adopt for older version of python3

How I did it
Changes:
Individual subdirs for each dir to be mounted
subprocess args made compatible with older version of python3 (tested in version 3.5.3)

How to verify it
Simulate read-only state
Run this script
Test ssh via new tacacs user (who had not logged in earlier)
@renukamanavalan renukamanavalan self-assigned this Oct 11, 2021
@abdosi abdosi merged commit e648290 into sonic-net:201911 Nov 20, 2021
stepanblyschak pushed a commit to stepanblyschak/sonic-utilities that referenced this pull request Apr 28, 2022
3ce8119 (HEAD -> 201911, origin/201911) [201911][port2alias]: Fix to get right number of return values (sonic-net#1907)
e648290 disk_Check: Scan & mount as RW when disk turns into Read-only (sonic-net#1872)

Signed-off-by: Abhishek Dosi <[email protected]>
@renukamanavalan renukamanavalan deleted the disk_check_201911 branch September 16, 2022 17:38
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2 participants