gollectz

README

What

collectd plugin for zfs disk stats using go and the go-libzfs C libs that talk directly to zfs apis, this should work well on zfsonlinux. things like :

used
available
usedbydataset
usedbychildren
usedbysnapshots
written
logicalused
volsize
reservatio

This was tested and used on:

• UBUNTU Linux 4.4.0-77-generic #98-Ubuntu SMP Wed Apr 26 08:34:02 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux, dkms/xenial-updates,xenial-updates,now 2.2.0.3-2ubuntu11.3, zfsutils-linux/now 0.6.5.6-0ubuntu16
• CENTOS 3.10.0-514.16.1.el7.x86_64 #1 SMP Wed Apr 12 15:04:24 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux, zfs-0.6.5.9-1.el7.centos.x86_64, zfs-release-1-3.el7.centos.noarch

Why

Because before I was using the "exec" plugin in collectd to run a bash script with sudo every x minutes and it was noticeble affecting performance when using AWS t2.micro instances.

This is an attempt to make getting metrics to collectd fast and NOT kill small machines.

How

This uses libzfslinux-dev, you should have this installed on your build machine.

Build

I am using golang version 1.8.3 I am assuming you have your go environment setup correctly, for example:

export GOPATH=$HOME/go
export PATH=$PATH:/usr/local/go/bin:$GOPATH/bin

Then build:

go get github.com/madedotcom/gollectz
go build github.com/madedotcom/gollectz

You could also use something like this: https://github.com/egidijus/go-builder

Put the produced binary in collect d plugins directory..

/usr/share/collectd/

Add custom types

vim /usr/share/collectd/custom_types.db

allocated     value:GAUGE:0:U
size     value:GAUGE:0:U
free     value:GAUGE:0:U

Tell collectd to read custom types:

vim /etc/collectd.conf

TypesDB     "/usr/share/collectd/types.db" "/usr/share/collectd/custom_types.db"

Change the permissions so we run this as a root always:

chown root:root /usr/share/collectd/gollectz
chmod u+s /usr/share/collectd/gollectz

Create a plugin config file:

/etc/collectd.d/gollectz.conf

LoadPlugin exec
<Plugin "exec">
  Exec "nobody" "/usr/share/collectd/gollectz"
</Plugin>

More

If you would like to report other things, you can add more properties to monitor in this list:

var properties = []zfs.Prop{
    zfs.PoolPropSize,
    zfs.PoolPropFree,
    zfs.PoolPropAllocated,
}

Be aware that not all values are parsed correctly or at all by this plugin.

How to make RPM

Use the RPM FPM package builder docker

docker run -it --rm -v $(pwd):/builder/packages/gollectz -w=/builder/packages/gollectz /build rpm-fpm-builder bash

then run this to create package

./build_rpm.sh

The FPM build script has this..

#!/bin/bash
set -ex
export BUILD_NUMBER=10

cd build
fpm -s dir \
    -t rpm \
    -n collectd-gollectz-zfs \
    --description "golang exec plugin to read disk stats from your ZFS pools" \
    -v 0.0.${BUILD_NUMBER} \
    --url "https://github.com/madedotcom/gollectz" \
    --license "MIT" \
    -m "Egidijus Ligeika" \
    --architecture noarch \
    -x "*/.git" \
    --verbose \
    --after-install scripts/after-install.sh \
    therpm/=/