searxng/docs/utils/lxc.sh.rst
Markus Heiser c8a6548592 [mod] utils/lxc.sh: detect conflict of docker & LXC in the iptables
Docker is blocking network of existing LXC containers / there is a conflict in
the iptables setup of Docker & LXC.  With this patch:

- utils/lxc.sh checks internet connectivity (instead of silently hang)
- Chapter "Internet Connectivity & Docker" describes the problem and made a
  suggestion for a solution a solution

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
2021-06-23 12:47:52 +02:00

6.3 KiB

utils/lxc.sh

With the use of Linux Containers (LXC) we can scale our tasks over a stack of containers, what we call the: lxc suite. The searx suite (lxc-searx.env <utils/lxc-searx.env>) is loaded by default, every time you start the lxc.sh script (you do not need to care about).

Before you can start with containers, you need to install and initiate LXD once:

$ snap install lxd
$ lxd init --auto

To make use of the containers from the searx suite, you have to build the LXC suite containers <lxc.sh help> initial. But be warned, this might take some time:

$ sudo -H ./utils/lxc.sh build

A cup of coffee later, your LXC suite is build up and you can run whatever task you want / in a selected or even in all LXC suite containers <lxc.sh help>.

Hint

If you see any problems with the internet connectivity of your containers read section internet connectivity docker.

If you do not want to build all containers, you can build just one:

$ sudo -H ./utils/lxc.sh build searx-ubu1804

Good to know ...

Each container shares the root folder of the repository and the command utils/lxc.sh cmd handles relative path names transparent, compare output of:

$ sudo -H ./utils/lxc.sh cmd -- ls -la Makefile
...

In the containers, you can run what ever you want, e.g. to start a bash use:

$ sudo -H ./utils/lxc.sh cmd searx-ubu1804 bash
INFO:  [searx-ubu1804] bash
root@searx-ubu1804:/share/searx#

If there comes the time you want to get rid off all the containers and clean up local images just type:

$ sudo -H ./utils/lxc.sh remove
$ sudo -H ./utils/lxc.sh remove images

Internet Connectivity & Docker

There is a conflict in the iptables setup of Docker & LXC. If you have docker installed, you may find that the internet connectivity of your LXD containers no longer work.

Whenever docker is started (reboot) it sets the iptables policy for the FORWARD chain to DROP [ref]:

$ sudo -H iptables-save | grep FORWARD
:FORWARD ACCEPT [7048:7851230]
:FORWARD DROP [7048:7851230]

A handy solution of this problem might be to reset the policy for the FORWARD chain after the network has been initialized. For this create a file in the if-up section of the network (/etc/network/if-up.d/iptable) and insert the following lines:

#!/bin/sh
iptables -F FORWARD
iptables -P FORWARD ACCEPT

Don't forget to set the execution bit:

sudo chmod ugo+x /etc/network/if-up.d/iptable

Reboot your system and check the iptables rules:

$ sudo -H iptables-save | grep FORWARD
:FORWARD ACCEPT [7048:7851230]
:FORWARD ACCEPT [7048:7851230]

Install suite

To install the complete searx suite (includes searx, morty & filtron) <lxc-searx.env> into all LXC use:

$ sudo -H ./utils/lxc.sh install suite

The command above installs a searx suite (see installation scripts). To get the IP (URL) of the filtron service in the containers use show suite command. To test instances from containers just open the URLs in your WEB-Browser:

$ sudo ./utils/lxc.sh show suite | grep filtron
[searx-ubu1604]  INFO:  (eth0) filtron:    http://n.n.n.246:4004/ http://n.n.n.246/searx
[searx-ubu1804]  INFO:  (eth0) filtron:    http://n.n.n.147:4004/ http://n.n.n.147/searx
[searx-ubu1910]  INFO:  (eth0) filtron:    http://n.n.n.140:4004/ http://n.n.n.140/searx
[searx-ubu2004]  INFO:  (eth0) filtron:    http://n.n.n.18:4004/ http://n.n.n.18/searx
[searx-fedora31]  INFO:  (eth0) filtron:    http://n.n.n.46:4004/ http://n.n.n.46/searx
[searx-archlinux]  INFO:  (eth0) filtron:    http://n.n.n.32:4004/ http://n.n.n.32/searx

To install a nginx <installation nginx> reverse proxy for filtron and morty use (or alternatively use apache <installation apache>):

sudo -H ./utils/lxc.sh cmd -- FORCE_TIMEOUT=0 ./utils/filtron.sh nginx install
sudo -H ./utils/lxc.sh cmd -- FORCE_TIMEOUT=0 ./utils/morty.sh nginx install

Running commands

Inside containers, you can use make or run scripts from the toolboxing. By example: to setup a buildhosts and run the Makefile target test in the archlinux container:

sudo -H ./utils/lxc.sh cmd searx-archlinux ./utils/searx.sh install buildhost
sudo -H ./utils/lxc.sh cmd searx-archlinux make test

Setup searx buildhost

You can install the searx buildhost environment into one or all containers. The installation procedure to set up a build host<buildhosts> takes its time. Installation in all containers will take more time (time for another cup of coffee).:

sudo -H ./utils/lxc.sh cmd -- ./utils/searx.sh install buildhost

To build (live) documentation inside a archlinux container:

sudo -H ./utils/lxc.sh cmd searx-archlinux make docs.clean docs.live
...
[I 200331 15:00:42 server:296] Serving on http://0.0.0.0:8080

To get IP of the container and the port number live docs is listening:

$ sudo ./utils/lxc.sh show suite | grep docs.live
...
[searx-archlinux]  INFO:  (eth0) docs.live:  http://n.n.n.12:8080/

Overview

The --help output of the script is largely self-explanatory:

../utils/lxc.sh --help

searx suite

../../utils/lxc-searx.env