A colleague has just published a newer build of an internal package to your local yum repository, but on the client `yum list available` still shows only the old version. Which command makes the client discard its cached repository metadata so the next transaction fetches it again?
LPIC-1 Exam 101-500, objective 102. Linux installation and package management easy
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How these questions are written — where each question comes from, what the verification ledger records, and what happens when one is found wrong.
The options
Correct yum clean all
Correct. It empties the cache under /var/cache/yum (or /var/cache/dnf), metadata included, so the repositories are read afresh on the next command.
Not correct yum clean packages
Wrong for this problem. That removes only the downloaded .rpm files from the cache; the stale metadata that decides which versions exist stays behind.
Not correct rpm --rebuilddb
Wrong. That rebuilds the local RPM database of installed packages under /var/lib/rpm and never touches repository metadata.
Not correct yum update
Wrong. It upgrades installed packages using whatever metadata is currently considered valid, which is exactly the stale copy you are trying to get rid of.
Why
Repository metadata is cached locally and considered fresh until metadata_expire, set in /etc/yum.conf or per repository, has passed; that is why a repository updated moments ago can stay invisible. `clean all` drops the cache, and `makecache` can then rebuild it immediately if you prefer not to wait for the next transaction. The distinction that matters is between the repository metadata cache and the local RPM database, which describes what is installed and is maintained only by rpm itself.
Where this comes from
- Cited
- manual page yum(8)
Practise this
Reading one question is not practice. The trainer will draw a short set from objective 102 and space the ones you get wrong.
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