Sandal is a basic, lightweight container system for Linux-embedded systems.
This project aims to have a container system which light weight and respects systems disk usage.
It utilizes the squashfs filesystem as a container image, so you can execute the container directly from the file, and easy to distribute it with portable media.
ARCH=amd64 # arm64, armv7, armv6, 386
wget https://github.com/ahmetozer/sandal/releases/latest/download/sandal-linux-${ARCH} -O /usr/bin/sandal
chmod +x /usr/bin/sandal
Multiple subcommands are available on the system for different usage purposes.
Executing a new container image with given options.
Examples:
sandal run -sq=homeas.sq -v=/run/dbus:/run/dbus -name=homeas -env-all \
-v=/mnt/homeassistant/config:/config /init
sandal run -sq=/mnt/sandal/images/homeas.sq -pod-ips="172.16.0.3/24;fd34:0135:0123::3/64" \
-ns-net=host -v=/run/dbus:/run/dbus -name=homeas -v=/mnt/homeassistant/config:/config /init
sandal run -sq=/mnt/sandal/images/octo.sq -env-all --ns-net=host --name=octo \
-pod-ips="172.16.0.4/24;172.16.0.5/24;fd34:0135:0123::4/64" -v=/mnt/octo:/octoprint/octoprint -devtmpfs=/mnt/external/ /init
export MY_SECRET_1=1234
export MY_SECRET_2=asdf
export MY_SECRET_3=aaaaa
sandal run -lw=/root/alpine -rm -env-pass=MY_SECRET_1 -env-pass=MY_SECRET_3 env
MY_SECRET_1=1234
MY_SECRET_3=aaaaa
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
SANDAL_CHILD=/var/lib/sandal/containers/232gG0pVhDa9u8U3v5e75O/config.json
Listing existing containers
Example:
sandal ps
NAME SQUASHFS COMMAND CREATED STATUS PID
22IQkaDNhRp9okqsewZL19 /mnt/sandal/images/homeas.sqfs /bin/bash 2024-05-11T22:48:59+01:00 exit 0 815519
22J7btLUSru7kuDRbkxLpi alpine.sqfs /bin/ash 2024-05-12T15:18:32+01:00 exit 0 927465
22J7dGBOWOz5sgrXiwVpRx alpine.sqfs /bin/ash 2024-05-12T15:20:38+01:00 exit 0 928541
22JbC5X2ks59IViFLkuVfG alpine.sqfs /bin/ping 2024-05-12T19:38:31+01:00 hang 957321 <-
22JbvIh9nbT1CpkNgrB8K1 alpine.sqfs /bin/ash 2024-05-12T19:32:28+01:00 exit 130 953991
sandal ps -dry
NAME SQUASHFS COMMAND CREATED STATUS PID
22IQkaDNhRp9okqsewZL19 /mnt/sandal/images/homeas.sqfs /bin/bash 2024-05-11T22:48:59+01:00 exit 0 815519
22J7btLUSru7kuDRbkxLpi alpine.sqfs /bin/ash 2024-05-12T15:18:32+01:00 exit 0 927465
22J7dGBOWOz5sgrXiwVpRx alpine.sqfs /bin/ash 2024-05-12T15:20:38+01:00 exit 0 928541
22JbC5X2ks59IViFLkuVfG alpine.sqfs /bin/ping 2024-05-12T19:38:31+01:00 running 957321 <- Note here
22JbvIh9nbT1CpkNgrB8K1 alpine.sqfs /bin/ash 2024-05-12T19:32:28+01:00 exit 130 953991
Listing namespace id's
sandal ps -ns
NAME PID CGROUPNS IPC MNT NET PIDNS USERNS UTS
22IQkaDNhRp9okqsewZL19 815519 4026532509 4026532507 4026532505 4026532510 4026532508 4026531837 4026532506
22J7btLUSru7kuDRbkxLpi 927465 4026532603 4026532601 4026532599 4026532604 4026532602 4026531837 4026532600
22J7dGBOWOz5sgrXiwVpRx 928541 4026532603 4026532601 4026532599 4026532604 4026532602 4026531837 4026532600
22JbC5X2ks59IViFLkuVfG 957321 4026532603 4026532601 4026532599 4026532604 4026532602 4026531837 4026532600
22JbvIh9nbT1CpkNgrB8K1 953991 4026532603 4026532601 4026532599 4026532604 4026532602 4026531837 4026532600
Delete container run files.
sandal rm alpine-1
Delete container files which they are started with -rm
flag and not running state
sandal clear
Creating squashfs from existing containers.
Note: this process requires podman or docker to get details for your container, and squashfs-tools
to create a squashfs archive image.
Example
podman run -it --rm --name cont1 alpine
sandal convert cont1
#[==================================================|] 92/92 100%
sandal run -sq=cont1.sqfs /bin/ping 1.0.0.1
To install squashfs-tools
#Debian, Ubuntu
sudo apt install squashfs-tools
#Fedora
sudo yum install squashfs-tools
#Alpine
apk add squashfs-tools
Kill container process
Example
sandal run -d -sq=cont1.sqfs --name cont1 /bin/ping 1.0.0.1
sandal kill cont1
sandal kill 22JbC5X2ks59IViFLkuVfG
Kill and restart container proccess with same args and current enviroment variable.
sandal run -d -sq=cont1.sqfs --name cont1 /bin/ping 1.0.0.1
sandal rerun cont1
Execute command under your container
sandal exec minecraft /bin/bash
Get last execution command.
sandal cmd minecraft
# Output
"sandal run -name=minecraft -keep -sq=/mnt/sandal/images/ubuntu.sq -pod-ips=172.16.0.4/24 -startup -d /sbin/runit"
Run all startup containers and watch in case of hang errors.
To enable systemd or runit, you can use sandal daemon -install
.
sandal daemon
2024/06/27 03:09:37 INFO daemon started
2024/06/27 03:10:01 INFO starting container=minecraft oldpid=102679
2024/06/27 03:10:03 INFO new container started container=minecraft pid=102759
2024/06/27 03:16:01 INFO starting container=homeas-2 oldpid=91491
2024/06/27 03:16:03 INFO new container started container=homeas-2 pid=103751
Get configuration file
sandal inspect minecraft
{
"Name": "minecraft",
"Created": 1719447001,
"HostPid": 102751,
"ContPid": 102759,
"LoopDevNo": 128,
"TmpSize": 0,
...}
At below, you can see some examples of different scenarios and combinations.
If your compiled application require system lib files, you can use distro squasfile and your second layer to start container.
mkdir -p myroot/bin/
cp myBinnary myroot/bin/
sandal run -name=mybinnary -keep -sq=/mnt/sandal/images/ubuntu.sq -lw="$HOME/myroot/" /bin/myBinnary
In this example, alpine is used and you can get alpine with below command
wget https://dl-cdn.alpinelinux.org/alpine/v3.20/releases/aarch64/alpine-minirootfs-3.20.1-aarch64.tar.gz
mkdir alpine
tar -xvzf alpine-minirootfs-3.20.1-aarch64.tar.gz -C alpine
rm alpine-minirootfs-3.20.1-aarch64.tar.gz
If you want to isolate your changes, you can start your system with lowerdir only.
sandal run -name=mybinnary -keep -lw="$HOME/alpine/" /bin/ash
With ramdisk
sandal run -name=alpine -keep -lw="$HOME/alpine/" -tmp=100 /bin/ash
With your binnary as layer
ls /myApp/bin/myapp
sandal run -name=mybinnarywithdistro -keep -lw="$HOME/alpine/" -lw="/myApp/" /bin/myapp
# or locate your configs
ls /myconfigs/
/etc/
dnsmasq.conf
hostpad.conf
sandal run -name=mybinnarywithdistro -keep -lw="$HOME/alpine/" -lw="/myApp/" -lw="/myconfig/ /bin/myapp
If you don't want to isolate your continer file system with overlay, you can use -v to mount your system
sandal run -name=alpine -v=/root/alpine:/ /bin/ash
You can directly use pysical disc with high performance with this approach as well
sandal run -name=mySsd -v=/mnt/myssd:/ /bin/bash
You can directly attach single binnary to container enviroment as well
sandal run -name=tunnel -v=/root/testlw/bosphorus:/bosphorus /bosphorus server
Altering routing table to only allow local access.
sandal run -v="/usr/bin/bosphorus" -rpp="/usr/bin/ip ro re unreachable default" -rpp="/usr/bin/ip ro add 10.0.0.0/8 via 172.16.0.1" --rpp="/usr/bin/ip ro show" /usr/bin/bosphorus
Installing curl before executing as init.
sandal run -v="/usr/bin/bosphorus" -rpe="/sbin/apk add curl" -lw="/root/alpine" /usr/bin/curl https://ahmet.network -lI
Save changes in different disk
sandal run -sq="/mnt/sandal/images/ubuntu.sq" -chd="/mnt/nvme1/develop/" /usr/bin/df -h
Filesystem Size Used Avail Use% Mounted on
overlay 916G 3.2G 867G 1% /