AppNeta cpe40 (Arista) - Docker Subnet. Conflict

Products

• AppNeta

Issue/Introduction

The cpe40 docker subnet is conflicting with our corporate network.

The default docker container subnet is 172.18.0.0/16

Resolution

To change the default docker subnet, please follow the below steps:

1. Backup Existing Startup Configuration

2. Run the below command (Update host IP as needed, do not use subnet IP):

config
event-handler docker-custom-bip
  trigger on-boot
  action bash [[ -f /etc/systemd/system/docker.service.d/custom_bip.conf ]] || { sudo mkdir -p /etc/systemd/system/docker.service.d/; echo -e "[Service]\nExecStart=\nExecStart=/usr/bin/dockerd --bip 192.168.154.1/24 -H fd:// --containerd=/run/containerd/containerd.sock" | sudo tee /etc/systemd/system/docker.service.d/custom_bip.conf >/dev/null; sudo systemctl daemon-reload; sudo systemctl restart docker; }
  exit
exit
copy run start
bash
[[ -f /etc/systemd/system/docker.service.d/custom_bip.conf ]] || { sudo mkdir -p /etc/systemd/system/docker.service.d/; echo -e "[Service]\nExecStart=\nExecStart=/usr/bin/dockerd --bip 192.168.154.1/24 -H fd:// --containerd=/run/containerd/containerd.sock" | sudo tee /etc/systemd/system/docker.service.d/custom_bip.conf >/dev/null; sudo systemctl daemon-reload; sudo systemctl restart docker; }
exit

3. Verify changes have taken effect (replace kc-cpe-arista with your container name):

bash docker exec -it kc-cpe-arista ip addr
[...]
3: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default
    link/ether 02:42:a3:8a:49:d7 brd ff:ff:ff:ff:ff:ff
    inet 192.168.154.1/24 brd 192.168.154.255 scope global docker0
       valid_lft forever preferred_lft forever