Amr Farid afarid

Overly aggressive CFS

We're looking at CPU bandwidth control via CFS:

https://www.kernel.org/doc/Documentation/scheduler/sched-bwc.txt

Reproduction program

Program does number of iterations, in each iteration we burn CPU in small chunks until we get 5ms of real time spent. On each iteration we also print how much

Kubectl output options

Let's look at some basic kubectl output options.

Our intention is to list nodes (with their AWS InstanceId) and Pods (sorted by node).

We can start with:

kubectl get no

Code is clean if it can be understood easily – by everyone on the team. Clean code can be read and enhanced by a developer other than its original author. With understandability comes readability, changeability, extensibility and maintainability.

General rules

Follow standard conventions.
Keep it simple stupid. Simpler is always better. Reduce complexity as much as possible.
Boy scout rule. Leave the campground cleaner than you found it.
Always find root cause. Always look for the root cause of a problem.

Design rules

Some of the Redis best practices content has moved

This content from this markdown file has moved a new, happier home where it can serve more people. Please check it out : https://docs.microsoft.com/azure/azure-cache-for-redis/cache-best-practices.

NOTE: Client specific guidance listed below is still valid and should still be considered. I will update this document once all content has been moved.

	# Profiling single php request
	The goal of this document is to give instructions for enable profiling

	Steps:
	## Enable php xdebug module
	```bash
	PHP_VERSION=7.2
	cat > /etc/php/7.2/apache2/conf.d/20-xdebug.ini <<EOF
	zend_extension=xdebug.so
	xdebug.profiler_enable_trigger=1

	# find the kube node of the running pod, appear next to hostIP, and note containerID hash
	kubectl get pod mypod -o json
	# -> save hostIP
	# -> save containerID

	# connect to the node and find the pods unique network interface index inside it's container
	docker exec containerID /bin/bash -c 'cat /sys/class/net/eth0/iflink'
	# -> returns index

	# locate the interface of the node

	"""
	Copies all keys from the source Redis host to the destination Redis host.
	Useful to migrate Redis instances where commands like SLAVEOF and MIGRATE are
	restricted (e.g. on Amazon ElastiCache).

	The script scans through the keyspace of the given database number and uses
	a pipeline of DUMP and RESTORE commands to migrate the keys.

	Requires Redis 2.8.0 or higher.