Docker

Note

This package is not supported in NethServer Enterprise

Docker is an open platform for developing, shipping, and running applications. Docker enables you to separate your applications from your infrastructure so you can deliver software quickly. With Docker, you can manage your infrastructure in the same ways you manage your applications.

Warning

Docker is customised to NethServer and the firewall layer. The default bridge docker0 is enabled to provide compatibility, however the official docker documentation stated on why you should not use it. Docker with NethServer comes with 3 other networks called aqua, aeria and macvlan.

Official documentation

The purpose of this documentation is to help you to install docker and enable the Portainer user interface. However all docker relative issues should be reported to the documentation or to the docker community.

The official documentation of docker can be found at : https://docs.docker.com/get-started/overview/

Installation

Install from the Software Center or use the command line:

yum install nethserver-docker

Docker repository

The official repository of docker is bundled but not enabled, the upgrade might break the running containers. It is advised to stop all containers before to upgrade docker-ce.

To upgrade to the latest stable version of docker:

yum update --enablerepo=docker-ce-stable

to enable it permanently:

config setprop docker enableRepository enabled
signal-event nethserver-docker-update

Configuration

If you have a free block device (required for production environments) assign it to Docker before starting it for the first time

config setprop docker DirectLvmDevice /dev/sdb
signal-event nethserver-docker-update

Review the current settings with

config show docker

Network, is the IP network address of the aqua zone IpAddress, is the IP address of the Docker host in the Network above

After each change, you have to restart docker

signal-event nethserver-docker-update

Web user Interface

Portainer is an interface to manage all containers running on this host or eventually on remote hosts, a property must be enabled before to create the portainer

config setprop portainer status enabled
signal-event nethserver-docker-update

The URL of portainer is https://<IP>:980/portainer/ . The first time it is accessed, it asks to generate the administrative credentials.

Portainer is itself a container without important data, except the admin credential. Therefore if you need to do a clean installation you can remove the container and the data stored in /var/lib/nethserver/portainer.

The official documentation of portainer can be found at : https://www.portainer.io/documentation/

Default network

The default bridge docker0 is allowed in the firewall of NethServer, any ports or the containers will be opened through shorewall. Any docker howto is supposed to be compatible.

Example of nginx container on port 9001:

docker run  -dit --name nginx-test-01 -p 9001:80 --restart=unless-stopped nginx:alpine nginx-debug -g 'daemon off;'

Aqua network

A new firewall zone and docker network, aqua. Basically, containers are attached to aqua and they can talk each other. IP traffic from other zones, like green and red must be configured with the usual Firewall rules and Port forwarding pages.

For an integration with system services, connections from the aqua zone are allowed to the MySQL/MariaDB port 3306. it means that a docker running on aqua can use the mysql database on the server. More port rules can be opened to the system services running on the server with a esmith db command (these rules allow only the containers to connect to a service running on the server):

db dockrules set customName aqua TCPPorts 5141,5142 UDPPorts 5143,5144 status enabled
signal-event firewall-adjust

You have to specify to use the network aqua for your container, the default docker0 is another network. Each container on the network aqua will have an IP from the network 172.28.0.0/16. They can communicate each other and the server can ping each container.

For example (pihole on aqua with a static IP):

docker run -d --name nxfilter -v nxfilter-conf:/nxfilter/conf -v nxfilter-log:/nxfilter/log \
-v nxfilter-db:/nxfilter/db -e TZ=Europe/Vienna \
--net=aqua --ip=172.28.0.10/16 --restart=unless-stopped packetworks/nxfilter-base:latest

Aeria network

NethServer docker provides a docker network named Aeria that is bound to a bridge. The container will have an IP attributed by the dhcp server of your local network, all containers will communicate like any servers on your network.

For the bridge creation the server manager could be used, if you have already installed the account provider Samba AD (nethserver-dc), you have already a bridge called br0.

Warning

A bridge is mandatory to aeria, you must accomplish this step before to go further: ip a can valid that the bridge is up and workable. The same bridge cannot be shared among aeria and macvlan, it is a docker limitation.

To enable the Aeria network, the bridgeAeria property has to be set to the name of the bridge

config setprop docker bridgeAeria br0
signal-event nethserver-docker-update

The NethServer DHCP module can be used to set IP addresses for the docker containers. By default docker containers use random MAC addresses so fixed ones need to be set for the containers to make DHCP reservations work.

Here is an example for starting pihole in the Aeria network and set the MAC address

docker run -d --name pihole -e TZ="Europe/Vienna" -e WEBPASSWORD="admin" \
-v "$(pwd)/etc-pihole/:/etc/pihole/" \
-v "$(pwd)/etc-dnsmasq.d/:/etc/dnsmasq.d/" --cap-add NET_ADMIN \
--net=aeria --mac-address=0e:6f:47:f7:26:1a --restart=unless-stopped pihole/pihole:latest

Aeria uses a docker plugin. To update the plugin

signal-event nethserver-docker-plugin-update

Macvlan

A container use TCP/UDP ports to communicate outside of the server, this is the default networking. However your container could need to get a real IP on your network. Like this it will be reachable with http://IPofYourContainer instead of http://IPofYourServer:port. A specific configuration like a DNS sinkhole (as pihole) must have an IP, because it might break the DNS resolution of your server. Therefore with a different IP, all hosts of your network will use the services of pihole like if it was on another server.

Note

The difference between macvlan and aeria is that macvlan is not a plugin, it is an official network driver.

NethServer docker provides a docker network named macvlan that must be bound to a bridge. Each container on the network macvlan must have a relevant IP in the range assigned to macvlan, all containers will communicate like any servers on your network.

For the bridge creation the server manager could be used, if you have already installed the account provider Samba AD (nethserver-dc), you have already a bridge called br0.

Warning

A bridge is mandatory to macvlan, you must accomplish this step before to go further: ip a can valid that the bridge is up and workable. The same bridge cannot be shared among aeria and macvlan, it is a docker limitation.

Macvlan must be created by filling some important parameters, the goal is to create a container with an IP on your network, each parameter depends from your network setting.

  • macVlanGateway : It is the gateway of your network, generally speaking it is your router (here 192.168.1.1)
  • macVlanLocalNetwork : It is the full network of your router (here 192.168.1.0/24 from 192.168.1.1 to 192.168.1.255)
  • macVlanNetwork : It is the restricted IP for macVlan0 (here 192.168.1.224/27, you can use 30 IP for your containers from 192.168.1.225 to 192.168.1.254)
  • macVlanNic : It is the network interface where to run macvlan (br0 here)

Create the network

config setprop  docker macVlanGateway 192.168.1.1 macVlanLocalNetwork 192.168.1.0/24 macVlanNetwork 192.168.1.224/27 macVlanNic br0

Then trigger the event

signal-event nethserver-docker-update

You have to specify to use the network macvlan for your container, the default docker0 is another network.

Docker creation example on macvlan

docker run --net=macvlan -dit --name nginx-test-02 --ip=192.168.1.225 --restart=unless-stopped nginx:alpine nginx-debug -g 'daemon off;'

The container can be contacted at the relevant IP

curl http://192.168.1.225

In case of the proposed CIDR doesn’t fit your need, you should have a look to an IP calculator

Issues

Please raise issues on community.nethserver.org.