Jesse Pretorius odyssey4me

Introduction

Due to the underlying networking services making use of tunnelling and packet tagging a situation may arise where instance network connectivity, especially when downloading large files or transferring files, is found to be unreliable.

This article describes how to adjust the instance to ensure that it uses a suitable MTU size so that packets are not dropped by the underlying infrastructure.

Note that the appropriate MTU size is delivered via DHCP by the underlying network service, but not all operating systems make use of the DHCP option to dynamically set the MTU size for the NIC. This document thus serves as a failback when then DHCP option is not used.

Symptoms

	#!/usr/bin/env python

	import argparse
	import json
	import re
	import sys
	import yaml

	from datetime import datetime
	from datetime import timedelta

	# Note: This test is executed on Ubuntu Trusty

	# do this on localhost (deployment host)
	# ensure that there's a local ssh private key
	ssh-keygen -t rsa -N '' -f ~/.ssh/id_rsa

	# now make sure that the public key is in the second host's authorized_keys
	# then do a test ssh connection to make sure it works, and to add the host
	# to known hosts

	- name: Create containers via host target
	hosts: localhost
	tasks:

	- name: Clean up previous tests
	lxc_container:
	name: "{{ item }}"
	state: absent
	with_items:
	- overlayfs1

	---
	cidr_networks:
	az1_container: 172.29.236.0/23
	az1_tunnel: 172.29.238.0/23
	az1_storage: 172.29.240.0/23
	az2_container: 172.29.242.0/23
	az2_tunnel: 172.29.244.0/23
	az2_storage: 172.29.246.0/23

	used_ips:

	rabbitmq_package_url: "{{ _rabbitmq_package_url }}"
	rabbitmq_package_version: "{{ _rabbitmq_package_version }}"
	rabbitmq_release_version: "{{ _rabbitmq_release_version }}"
	rabbitmq_package_sha256: "{{ _rabbitmq_package_sha256 }}"
	rabbitmq_package_path: "{{ _rabbitmq_package_path }}"

	---
	# This should be implemented in /etc/openstack_deploy/env.d/
	component_skel:
	galera:
	belongs_to:
	- galera_all


	container_skel:
	galera_container:

	" Remove old vi compatibility
	set nocompatible

	" Enable Syntax Highlighting
	filetype on
	filetype plugin on
	syntax enable
	set grepprg=grep\ -nH\ $*

	" Use spaces instead of tabs

	---
	#
	# Important required settings
	#

	# set haproxy to handle ssl offloading
	haproxy_ssl: true

	# configure the SSL certificates for haproxy
	# these file paths are on the deployment host

	# build locally (includes a fair amount of stuff and takes a bit of time)
	#lxc-create --name=template3 --template=ubuntu -- --release trusty --arch amd64 --packages openssh-server,python2.7,apt-transport-https,python-lxml
	#chroot /var/lib/lxc/template3/rootfs apt-get clean

	# use a downloaded image (much faster)
	lxc-create --name=template2 --template=download -- --dist ubuntu --release trusty --arch amd64
	chroot /var/lib/lxc/template2/rootfs apt-get install -y \
	openssh-server \
	python2.7 \
	apt-transport-https \