Limit total RAM & CPU usage of all docker containers combined

docker_slice_limit_total_ram_and_cpu.sh

#!/bin/bash

# https://unix.stackexchange.com/questions/537645/how-to-limit-docker-total-resources
# https://www.freedesktop.org/wiki/Software/systemd/ControlGroupInterface/

CPU_PERCENTAGE="90"
RAM_PERCENTAGE="90"

# Get total RAM in bytes
total_ram=$(grep MemTotal /proc/meminfo | awk '{print $2}')

# Calculate % of RAM
memory_limit=$(echo "scale=2; $total_ram * $RAM_PERCENTAGE / 100 / 1024 / 1024" | bc) # Convert to GB

# Create the systemd slice file
cat <<EOF | sudo tee /etc/systemd/system/docker_limit.slice
[Unit]
Description=Slice that limits docker resources
Before=slices.target

[Slice]
CPUAccounting=true
CPUQuota=${CPU_PERCENTAGE}%
MemoryAccounting=true
MemoryLimit=${memory_limit}G
EOF

# create the docker daemon configuration file
cat <<EOF | sudo tee /etc/docker/daemon.json
{
  "storage-driver": "devicemapper",
  "cgroup-parent": "docker_limit.slice"
}
EOF

# reload systemd daemon
sudo systemctl daemon-reload

# start the docker_limit slice
sudo systemctl start docker_limit.slice

# restart docker
systemctl restart docker



# verify it works with
#
# systemd-cgtop