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Proving skills, building evidence, and getting hired on ability: practical guides for engineers whose skills have outrun their CV.
Context deadline exceeded means a caller-imposed timeout elapsed before the work finished. How to find whose deadline fired in Kubernetes, and what was slow under it.
Exit code 127 means command not found; 126 means found but not executable. Both are shell verdicts on your entrypoint. Where containers hit them, verified live.
Exit code 139 means SIGSEGV: the process touched memory it did not own. Container-specific causes, a fast attribution path, and a live repro the naive test gets wrong.
ErrImagePull and ImagePullBackOff are one retry sequence, not two errors. Four root-cause families and the exact event line each leaves, verified on a live cluster.
OOMKilled is the kernel's memory verdict, on your limit or the node's. What the cgroup really counts, and the observed oom_score_adj numbers behind who dies first.
Exit code 143 means SIGTERM: your container was asked to stop and complied. When 143 is healthy, when it is a probe kill, and why Kubernetes still labels it Error.
CrashLoopBackOff is a symptom, not a cause. The last exit code and the time-to-death route you to the real failure. A diagnosis path with a runnable repro.
The definitional debate is settled and useless. What SRE and DevOps titles actually signal in job listings, which skills transfer, and how to read a JD past its title.
Exit code 137 means SIGKILL. The kernel OOM killer, a failed liveness probe, or an outside actor: a diagnosis path that tells the three apart, with a runnable repro.
No CS degree? Not the blocker you think. What actually filters candidates out, the signals that substitute for credentials, and a working plan.
Most portfolio advice produces identical toy projects nobody reads. What hiring managers actually look for, five projects worth building, and how to present them.
Practise diagnosing CrashLoopBackOff, ImagePullBackOff, Pending pods, unreachable Services and OOMKilled containers through real troubleshooting paths.
Support engineers already have production instincts most career switchers lack. Map support experience onto SRE competencies, close the real gaps, make the move.
The CKA is not the only way to show you can run Kubernetes in production. Here is what actually signals DevOps competence, and five things you can start doing this week.
How DevOps and SRE profiles actually get screened: where the six seconds go, what hiring managers care about, and how to stop optimising for signals nobody reads.