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--- userdoc:guest_lxc_container_command [2020/05/31 21:19]
abelbeck created
+++ userdoc:guest_lxc_container_command [2020/06/01 10:50] (current)
abelbeck
@@ Line 1: / Line 1: @@
 ====== Command via a Container ======
+There are occasions where a command might be useful within AstLinux, but it may use python, golang, etc. or is just large in comparison to the 50 MB size of the AstLinux image.  A LXC container can be a handy tool to add such a command.
+**Resource Usage:** (minimum)
+  * Memory: 100 MB
+  * Storage: 0.4 GB
+\\
+Below is an example how to add the ''lynx'' command line web browser.  The ''lynx'' container only runs when needed.
+First, it is assumed the ''lxcbr0'' interface is setup per the **[[userdoc:guest_lxc_container#quick_start_guide|Quick Start Guide]]** -> Enable LXC Support.
+Then from the CLI:
+  lxc-create -t download -n lynx -- -d debian -r buster -a amd64 --no-validate
+  service lxc restart
+  lxc-attach lynx
+    apt update
+    apt install lynx ca-certificates fping
+    exit
+Next, stop the ''lynx'' container and keep it from automatically starting.
+  lxc-stop lynx
+  sed -i 's/^lxc.start.auto=1/lxc.start.auto=0/' /var/lib/lxc/lynx/config
+Finally, create a wrapper script to start/stop the container and issue a command.
+Place this script at ''/mnt/kd/bin/lynx'' and give it ''chmod 755'' permissions.
+  #!/bin/sh
+  ##
+  ## lynx wrapper for LXC Debian 10 container
+  ##
+  ## generate a random uid
+  rand_uid=$((RANDOM % 4999 + 95000))
+  ## Destination IP to test when container network is active
+  ping_ip="8.8.4.4"
+  trap 'printf "Abort\n" >&2; lxc-stop lynx; exit 1' INT TERM EXIT
+  lxc-start lynx
+  printf "Waiting for container network to become active... "
+  lxc-attach lynx -u $rand_uid -- fping -q -r15 $ping_ip
+  printf "OK\n"
+  lxc-attach lynx -u $rand_uid -- lynx "$@"
+  lxc-stop lynx
+  trap - INT TERM EXIT
+  exit 0
+!!Tip ->!! If you edit ''/var/lib/lxc/lynx/config'' and assign a manual IP address, the container starts very quickly, whereas using DHCP it takes 4-6 seconds to establish the network.
+Test it!
+  /mnt/kd/bin/lynx https://www.astlinux-project.org
+\\
+!!Related Info ->!! **[[userdoc:guest_lxc_container|LXC container in AstLinux]]**