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Posts about monitoring

Build fully working zabbix server with database in seconds thanks to docker

To install zabbix server quickly zabbix comes with help as they have prebuild their product with docker images. There is lots of official zabbix images on dockerhub so it can just overwhelm you. There are mixes of all different possibilities like zabbix with mysql or postgres or either sqlite, zabbix served bt nginx or apache or java gateway. Depending on stack which is closest to you you can easily build docker-compose that will just run selected stack in seconds. My pick was nginx mysql so to set up fully running zabbix server we need 3 images

  • mysql-server

  • zabbix-web - web interface

  • zabbix-server - main zabbix process responsible for polling and trapping data and sending notifications to users.

In addition you can add postfix mail server for notifying users but its not a must as you can use your own mail server if so - just remove postfix service from example below.

Notice(you may want to use some specific versions or alpine versions for production env)

Create some directory (directory name is crucial here for visibility and future maitenance of your containers and volumes or networks as the name will be used as prefix for docker containers created by docker-compose and also volumes directories so it will be easier to identify in future which volume belongs to which stack In Ubuntu volumes are usually being kept in/var/lib/docker/volumes but you can mount any directory from host by just specifying absolute or relative path in service configuration so for instance for mysql in example to mount mysql_data_dir just outside of our containers folder

  - '../mysql_data_dir:/var/lib/mysql'

Now within directory create docker-compose.yml with selected technologies in my case it is: #docker-compose.yml

version: '3'

    image: mysql:latest
    restart: always
      - '3336'
      MYSQL_ROOT_PASSWORD: 'my_secret_password'
      MYSQL_USER: 'zabbixuser'
      MYSQL_PASSWORD: 'zabbix_password'
      MYSQL_ROOT_HOST: '%'
      - 'mysql_data_dir:/var/lib/mysql'

    image: zabbix/zabbix-server-mysql
      - "db:mysql"
      - "postfix:postfix"
      MYSQL_ROOT_PASSWORD: 'my_secret_password'
      MYSQL_USER: 'zabbixuser'
      MYSQL_PASSWORD: 'zabbixpassassword'
      DB_SERVER_HOST: 'mysql'

    image: zabbix/zabbix-web-nginx-mysql
      - '7777:80'
      - "db:mysql"
      - "zabbix-server:zabbix-server"
      - "postfix:postfix"
      MYSQL_ROOT_PASSWORD: 'my_secret_password'
      MYSQL_USER: 'zabbixuser'
      MYSQL_PASSWORD: 'zabbixpassassword'
      DB_SERVER_HOST: 'mysql'
      ZBX_SERVER_HOST: "zabbix-server"
      PHP_TZ: "Europe/London"
    image: catatnight/postfix
    hostname: support
      - smtp_user=admin:my_password
      - "25:25"
      - "25"
      - /etc/nginx/ssl/postfix:/etc/postfix/certs
      - /etc/nginx/ssl/postfix:/etc/opendkim/domainkeys
    driver: local

The above solution is just enough to start zabbix server up and running in couple seconds. To do it just run: .. code-block:: bash

sudo docker-compose up

Thats it!!! You now have your zabbix running on port 7777

So what happened here docker-compose up has build and runned 3 containers by running zabbix container it discovered there are no tables in mysql and has built them.

Now you just need to add agents/servers you want to monitor. Check out adding agent in separate post

Versions: (versions I've used in this example Feb 2018):

Docker-compose: 1.17.0, build ac53b73 Docker: 17.09.1-ce, build 19e2cf6 Kernel: 4.13.0-36-generic System: Ubuntu 16.04.3 LTS

Adding zabbix agent to server

Zabbix is very powerfull tool which its using agents (or SNMP) to monitor server resources. Adding agent is easy but I had couple problems doing that when I used agent straight from my ubuntus (16.04.3) repo as there was no encryption functionality in this agent well I guess so as agent didn't recognize tls psk configuration so not very nice as by installing agent straight form repo with "sudo apt-get update && sudo apt-get install zabbix-agent" I had limited functionality and unencrypted server-agent traffic. So there are 2 options we can install zabbix agent or use zabbix agent docker container. Adding zabbix agent to host system. For current day 3.2 is the latest so please change latest accordingly of how this artcile is old. wget sudo dpkg -i zabbix-release_3.2-1+xenial_all.deb sudo apt-get update apt-get purge zabbix-agent #remove previous if installed apt-get install zabbix-agent

Now there are 3 basic options that need to be changed in agent config file: /etc/zabbix/zabbix_agentd.conf

Server=ip of zabbix server ServerActive=ip of zabbix server Hostname=My host name

sudo service zabbix-agent restart

Add host to server through web interface:

In server go to Configuration-> Hosts -> Create host type in host name visible name public IP address opf your agent.Select group and add agent. Next is to select templates so add services you need to monitor (here linux + mysql : Template DB MySQL, Template OS Linux) after saving you should see green ZBX available label on Hosts screen Notice : I couldnt see zbx agent green icon until I added linux template / or zabbix agent template.

Seurity - Setting up PSK encryption:

sh -c "openssl rand -hex 32 > /etc/zabbix/zabbix_agentd.psk" Now add below lines to /etc/zabbix/zabbix_agentd.conf TLSConnect=psk TLSAccept=psk #each identity id must be different for each serverr connected to one zabbix server TLSPSKIdentity=PSK SOMETHING TLSPSKFile=/etc/zabbix/zabbix_agentd.psk sudo service zabbix-agent restart Get generated key string: cat /etc/zabbix/zabbix_agentd.psk and add encryption in zabbix server web interface : In server go to Configuration-> Hosts -> my host->encryption

Select: Connections to host PSK connections from host PSK PSK identity: PSK SOMETHING (same as in zabbixagent config file) PSK: the hash generated (content of /etc/zabbix/zabbix_agentd.psk file on agent ) now there should be greebn psk lablel and all our traffice will be encrypted

Adding mysql monitoring option:

add user credentials for mysqlclient on agent server: mysql > grant all privileges on . to zabbix@'%' identified by 'zabbixuserpassword'; use localhost or host you will be accessing mysql from % is just for test purpose to eliminate authentication problems.

Out of the topic - something about mysql remote connections and security: My best practice is not to have any remote access like @'%' to mysql on any server I manage its just dangerous and anyone can try bruteforcing and try to connect to our mysql server. Another way I saw in many places if admin creates @'%' accesses they use it without any encryption so there is plain text traffic comming from mysql-server/postgres straight to users computer which is not good (MITM etc). The best would be to have your mysql server set up with ssl certificate but its not popular practice as may be time consuming for setting up and for connecting to such server (preatty easu in mysql-workbench). Faster way to encrypt your mysql confidential data traffic is to use ssh tunnel but there is a limitation here user that needs access to mysql data needs to have ssh access to the server if this is an option just define users with localhost as source like my_db_user@localhost this is safer as you cant guarantee mysql users competence so best practice is to prevent having '%', to double secure this method do not to expose 3306 to the public and only allow localhost(unix socket) and (remember mysqlclient unixsocket/ ip connection) to be able to connect through this port. In dockerized mysql instances when I need it to be visible I just do ports config like then it will be visible to host machine only. but if user wont have ssh access to the server then only option you have is using ssl cert. So remember having user@'%' or even user@'some_ip' you still without ssl or ssh the traffic from mysql-server is still unencrypted.

Ok comming back to mysql monitoring config: add client to my.cnf in /etc/mysql or to /etc/mysql/conf.d/mysql.cnf

[client] user = zabbix password = zabbixuserpassword port = 3326 host =

add myu.cnf

mkdir -p /var/lib/zabbix/ cd /var/lib/zabbix ln -sv /etc/mysql/my.cnf

service zabbix-agent restart

Now you can add mysql template items in zabbix server .

select linux templates to see agent visibility

bug in default userparameter_mysql agent file

cat /etc/zabbix/zabbix_agentd.d/userparameter_mysql.conf redirect error to stdout to grep later,HOME=/var/lib/zabbix mysqladmin ping 2>&1 | grep -c alive previously was,HOME=/var/lib/zabbix mysqladmin ping | grep -c alive so grep didnt work

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