User talk:Jch/consul

This material is work-in-progress ... Do not follow instructions here until this notice is removed. (Last edited by Jch on 20 Apr 2015.)

Consul

Introduction

This page is currently my experimental log about consul on AL.

Downloaded package: consul-0.5.0-r0.apk from http://repos.mauras.ch/alpinelinux/x86_64/

Will prepare 5 KVM: 3 consul server (in run-from-ram mode) and 2 consul agent (a SAN (NBD) and a LXC host in data mode) on an isolated network.

We will experiment to find the right spec to allocate the consul servers for 100 to 1000 agents.

We plan to orchestrate our VM fleet based on consul events, envconsul and consul-template. All with ash scripts and smart setup.

We combine our PXE servers and the consul ones to inherit from the consul resilence (consul leader) to offer high-availability (HA) (but still in ram only) to the PXE service.

Install

We will just focus on the consul installation and configuration parts.

wget http://repos.mauras.ch/alpinelinux/x86_64/consul-0.5.0-r0.apk
apk add consul-0.5.0-r0.apk --allow-untrusted --force

Configuration

Consul v0.5.0
Consul Protocol: 2 (Understands back to: 1)

By default, there are 4 files in /etc/consul

acl.json.sample      encrypt.json.sample  server.json          tls.json.sample

Configuration Server

rc-service consul start

doesn't work even if

screen -m -d -S consul consul agent -config-dir=/etc/consul

does.

The HTTP API seems denied.

DNSmasq with consul

apk add dnsmasq
mkdir -p /etc/dnsmasq.d
echo "server=/consul/127.0.0.1#8600" > /etc/dnsmasq.d/10-consul
echo "resolv-file=/etc/resolv.dnsmasq" > /etc/dnsmasq.d/20-resolv
echo "nameserver ${DNS1}" > /etc/resolv.dnsmasq
echo "nameserver ${DNS2}" >> /etc/resolv.dnsmasq
echo <<EOF > /etc/conf.d/dnsmasq
MASQ_OPTS="--user=dnsmasq --group=dnsmasq --interface=eth0 --conf-dir=/etc/dnsmasq.d"
EOF
rc-service dnsmasq start

Configuration Agent

We need to lauch the consul service after being able to read the IP address of the PXEserver involved.
This particuliar address will be used to join the consul cluster as agent.

# read IP addr of PXEserver
# consul agent -join ${IP_PXEserver}

Usage

Machines discovery

List machines = list members

list PXEservers = list servers

whois active.PXEservers = get leader

Services discoevry

Register service

List services

Key/Value storage

k/v