How to check the integrity (checksums) of files when booting Linux?

Question

linux

Guys, tell me, there is a task from the management at all costs to check (verify) the integrity of the system files (a certain list of files) when the system boots. Those. there is a certain list of files and their checksums (MD5 or SHA-1 or other), when downloading, the integrity of the files should be verified (matching the checksums of the file and the standard), if everything is fine, then we load, if not, the server stops.
How much Google - did not find such a solution. Can you tell me

Answer 1

See nexthop
's answer Or

1. Make a list of files and their checksums.
   
2. Write a script that md5sumperforms checksum verification against this list using
   
3. In case of mismatch of amounts - notification to the administrator and haltthe server
   
4. Run script on server startup
   

Answer 2

sha1sum -c - <<EOF
a75....41e4774a  file1
9bc...864375f4e  file2
EOF

Well, where to shove it and how to process it depends on the specific system and task, stage.

Answer 3

rsync can check checksum after loading, for example. What is the difficulty?

Answer 4

It's not clear what the problem is. You create a list of the necessary files with their checksums and do a check on upload. The check will take from a few seconds of time (if the list is short) to probably several hours (if the list is long).