RHCSA
862 incident response problems that help with RHCSA prep.
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All problems (862)
LINUX-090Systemd cgroup memory limit kills the helper process and the main service logs look unrelatedThe application seems to fail in an unrelated code path, but the hidden cause is a helper process being OOM-killed inside the unit's cgroup budget.LinuxAdvanced18 minProLINUX-080XFS project quota silently blocks writes inside the container content pathThe filesystem still has free space, but one workload starts failing writes because a project quota limit was reached on the specific content subtree it uses.LinuxAdvanced18 minProLINUX-276A hostonly dracut image excludes the driver needed only on the disaster recovery host class during a failover rehearsalThe primary systems boot fine while the recovery host cannot bring up the device path it depends on. Normal traffic masked the issue until the standby or alternate path became active under rehearsal conditions.LinuxAdvanced19 minProLINUX-114An LVM snapshot merge is scheduled but initramfs is never rebuilt and the root rollback fails on rebootThe rollback plan seems prepared, yet boot falls apart because the early userspace image does not know about the new storage state.LinuxAdvanced19 minProLINUX-1229An nftables ruleset looks restored but one legacy iptables service replays a stale NAT table on bootThe new ruleset is correct on disk, yet after restart translated traffic behaves as if the old table still owns packet flow.LinuxAdvanced19 minProLINUX-078nftables set refresh leaves stale IP entriesThe firewall update appears to run, but some stale members stay active because the atomic update path failed halfway and the old set was never swapped cleanly.LinuxAdvanced19 minProLINUX-081OverlayFS upperdir fills the root filesystem while the underlying data volume still looks emptyContainer workloads write successfully for a while, but the host runs out of space because the upper layer resides on root and not on the large data device operators are watching.LinuxAdvanced19 minProLINUX-088SELinux policy module loads successfully but a file transition rule never matches the deployed pathThe custom policy is present, yet denials continue because the actual path used in deployment does not trigger the transition rule the author expected.LinuxAdvanced19 minProLINUX-087Package rollback restores binaries but not the migrated systemd unit dependency graphThe older package version is back, yet the service still behaves incorrectly because the dependency units changed in a later release and were not reverted with the package.LinuxAdvanced20 minProLINUX-067chrony source priority drift pushes one site out of acceptable Kerberos time skewNTP is technically running everywhere, but one location follows a lower-quality source and drifts just far enough to break time-sensitive authentication.LinuxAdvanced21 minProLINUX-065LVM snapshot reaches 100 percent and the application filesystem stallsThe origin volume still has free space, but writes slow or freeze because the snapshot copy-on-write area filled and the backup workflow never released it.LinuxAdvanced22 minProLINUX-054nftables hotfix disappearsA manual packet filter change solves the immediate outage, but the next reload or reboot brings back the old policy because the permanent source of truth was never updated.LinuxAdvanced23 minProLINUX-007TLS verification intermittently failing due to system time driftCovers a system-time problem where the application is fine but certificate validity-time checks drift.LinuxAdvanced23 minProLINUX-035PAM limits are raised but the systemd service still hits too many open filesInteractive shells inherit the new limit correctly, but the daemon still fails under load because its service-level limit remains unchanged.LinuxAdvanced25 minProLINUX-026Swap activity stays high after memory spike is goneSwap activity stays high (Timeouts and Latency) is a hands-on troubleshooting drill. The incident is over, but swap churn remains elevated and keeps latency unpredictable for the rest of the day. Linux Service Operations needs to be checked by narrowing scope, recent change, a...LinuxAdvanced25 minProLINUX-058XFS log recovery loop continues after an unclean volume detachThe block device is back online, but the filesystem still refuses to mount cleanly because the recovery path never completed and the operator keeps retrying the same mount blindly.LinuxAdvanced25 minProLINUX-023Ephemeral disk pressure kills cache but not the root causeEphemeral disk pressure kills cache but not the root cause is a hands-on troubleshooting drill. Cleaning temp files buys time, but write amplification from another process quickly recreates the same disk pressure. Linux Service Operations needs to be checked by narrowing scope...LinuxAdvanced26 minProLINUX-040Overlay mount reports no space left on device while df still shows free blocksContainer creation fails with a storage error even though normal disk and inode checks look healthy, pointing to overlay, mount, or lower-level storage limits rather than a simple full disk.LinuxAdvanced27 minProLINUX-029Readonly remount happens only after storage latency burstThe filesystem looks healthy most of the time, but latency spikes trigger IO errors that remount the volume as readonly.LinuxAdvanced28 minProLINUX-1604A chrony configuration fix is present and one node still driftsOne node still drifts after a chrony configuration fix.LinuxIntermediate7 minPro