-
Kubernetes Probes Are Not Your Dependency Strategy
Designing failure semantics across ingress, Java services, clients, and serverless The most dangerous thing about Kubernetes probes is not that teams misunderstand their definitions. It is that teams forget probes are actions, not just signals. A failed readiness probe changes routing. A failed liveness probe kills a process. A failed startup probe can stall a…
-
Upgrading Nginx Ingress Controller from V1.1.1 to V1.12.0
While upgrading the Nginx Ingress Controller, I encountered a few issues with the controller pod startup. Here are the problems and their solutions: 1. Cross-namespace secret is not supported If you have your mTLS CA as a secret in the namespace where the controller is deployed, you’ll face this issue. After the upgrade, the ingress…
-
High System CPU usage
After upgrading a webserver running Apache to Debian Jessie (from Wheezy), I noticed that the system CPU usage was higher. Running an strace on one of the Apache processes was giving me very little info: strace -c -p 10112 Process 10112 attached – interrupt to quit ^CProcess 10112 detached % time seconds usecs/call calls errors…
-
HHVM notes
Impressive throughput improvements (>100%) with the app that I am working on. phpinfo() doesn’t output what you would expect. xhprof output_dir doesn’t get read from ini files, need to set that up in the constructor of XHProfRuns_Default. Set hhvm.server.thread_count to a high value (>=MaxRequestWorkers), otherwise a few slow MySQL queries could bring the server to…
-
Keepalived instance not entering FAILED state
When a monitored interface goes down, the instance immediately enters FAILED state and the other instance gets into the MASTER state. But, if you have a script block to check – say you are monitoring HAProxy – and HAProxy goes down the MASTER will not enter FAILED state, unless you do this: Set the weight…