Document latest problems with docker images and resource reclaimation, add docker performance checks in the monitoring scripts, helpers to filter the logs

1 files changed, 21 insertions, 0 deletions

diff --git a/docs/users.txt b/docs/users.txt
new file mode 100644
index 0000000..c28f400
--- /dev/null
+++ b/docs/users.txt
@@ -0,0 +1,21 @@
+Dockerfiles
+===========
+ - Long (many-layer) Dockerfiles may cause a significant disruption to the OpenShift cluster (far behind just performance penalty
+ of working with this layers). Currently, it is imperative to reduce the number of intermediate images resident on the OpenShift nodes.
+    * The better approach is to optimize Dockerfiles: All ENV defined at once, as few ARG as possible, signle COPY, and a single RUN to
+    setup everything.
+    * Alternatively, the final image can be squashed with 'docker build --squash ...' (enable experimental features in docker daemon). 
+    However, this is incompatible with OpenShift build process.
+ If optimizing already running applications, it is not enough just to re-build images. Old images could be referenced by the old 
+ 'rc' left in the system or even stopped containers lost by OpenShift infrastructure. 
+    * Check if old images still present (https://github.com/TomasTomecek/sen is only application I am aware of capable of showing it)
+    * See maintenance section how to get rid if old images are still present
+
+Deployments
+===========
+ - CronJobs is currently a bit problematic and periodically cause some lost resources, etc. They can be used if necessarily, but it better
+ to minimize. In any case, it is crucial to minimize size of frequently scheduled Job containers (otherwise large I/O). 
+
+
+Storage
+=======