fix: use an alternate subnet for the docker bridge network

README.md

@@ -201,6 +201,17 @@ Default: `"{{ hpc_install_nvidia_container_toolkit }}"`
 
 Type: `bool`
 
+### hpc_docker_subnet
+
+The default docker bridge interface address and subnet configuration of 172.17.0.1/16 conflicts with the subnets Azure CycleCloud uses for internal physical cluster networks.
+
+To avoid this conflict with the Azure CycleCloud networks, the system role will configure the docker interface with a 10.88.0.1/16 address and subnet.
+However, if this is inappropriate for the cluster being deployed, the subnet can be customised to any private subnet using this variable.
+
+Default: `10.88.0.1/16`
+
+Type: `string`
+
 ### hpc_install_moneo
 
 Whether to install the Azure Moneo monitoring tool.

defaults/main.yml

@@ -28,6 +28,7 @@ hpc_build_openmpi_w_nvidia_gpu_support: true
 hpc_install_moneo: true
 hpc_install_nvidia_container_toolkit: true
 hpc_install_docker: "{{ hpc_install_nvidia_container_toolkit }}"
+hpc_docker_subnet: 10.88.0.1/16
 hpc_install_azurehpc_health_checks: "{{ hpc_install_nvidia_container_toolkit }}"
 hpc_tuning: true
 hpc_sku_customisation: true

tasks/docker-subnet.yml

@@ -0,0 +1,36 @@
+---
+- name: Ensure docker config directory exists
+  file:
+    path: "{{ __hpc_docker_conf_dir }}"
+    state: directory
+    owner: root
+    group: root
+    mode: '0755'
+
+- name: Check if daemon.json exists
+  stat:
+    path: "{{ __hpc_docker_conf_file }}"
+  register: __hpc_docker_conf_stat
+
+- name: Slurp file if it exists
+  slurp:
+    src: "{{ __hpc_docker_conf_file }}"
+  register: __hpc_docker_daemon_json_raw
+  when: __hpc_docker_conf_stat.stat.exists and __hpc_docker_conf_stat.stat.size > 0
+
+- name: Write the updated JSON safely
+  copy:
+    content: "{{ updated_daemon_config | to_nice_json }}"
+    dest: "{{ __hpc_docker_conf_file }}"
+    owner: root
+    group: root
+    mode: '0644'
+    validate: '/usr/bin/python3 -m json.tool %s'
+  vars:
+    updated_daemon_config: >-
+      {{
+        (__hpc_docker_daemon_json_raw.content | b64decode | from_json
+        if (__hpc_docker_daemon_json_raw.content is defined)
+        else {})
+        | combine({"bip": hpc_docker_subnet | default('10.88.0.1/16')})
+      }}

tasks/main.yml

@@ -941,6 +941,9 @@
       register: __hpc_docker_packages_install
       until: __hpc_docker_packages_install is success
 
+    - name: Configure Docker bridge network address range
+      include_tasks: tasks/docker-subnet.yml
+
     - name: Enable and start Docker service
       service:
         name: docker

vars/main.yml

@@ -21,6 +21,8 @@ __hpc_microsoft_prod_rpm_key: https://packages.microsoft.com/keys/microsoft.asc
 __hpc_base_packages:
   - pssh
 
+__hpc_docker_conf_dir: /etc/docker
+__hpc_docker_conf_file: "{{ __hpc_docker_conf_dir }}/daemon.json"
 __hpc_rdma_rename_path: /usr/lib/udev/rdma_rename
 
 __hpc_dkms_packages: