[jjo] add DIND support to contrib/ (#3468)

* [jjo] add DIND support to contrib/

- add contrib/dind with ansible playbook to
  create "node" containers, and setup them to mimic
  host nodes as much as possible (using Ubuntu images),
  see contrib/dind/README.md

- nodes' /etc/hosts editing via `blockinfile` and
  `lineinfile` need `unsafe_writes: yes` because /etc/hosts
  are mounted by docker, and thus can't be handled atomically
  (modify copy + rename)

* dind-host role: set node container hostname on creation

* add "Resulting deployment" section with some CLI outputs

* typo

* selectable node_distro: debian, ubuntu

* some fixes for node_distro: ubuntu

* cpu optimization: add early `pkill -STOP agetty`

* typo

* add centos dind support ;)

* add kubespray-dind.yaml, support fedora

- add kubespray-dind.yaml (former custom.yaml at README.md)
- rework README.md as per above
- use some YAML power to share distros' commonality
- add fedora support

* create unique /etc/machine-id and other updates

- create unique /etc/machine-id in each docker node,
  used as seed for e.g. weave mac addresses

- with above, now netchecker 100% passes WoHooOO!
  🎉 🎉 🎉

- updated README.md output from (1.12.1, verified
  netcheck)

* minor typos

* fix centos node creation, needs earlier udevadm removal to avoid flaky facts, also verified netcheck Ok \o/

* add Q&D test-distros.sh, back to manual /etc/machine-id hack

* run-test-distros.sh cosmetics and minor fixes

* run-test-distros.sh: $rc fix and minor formatting changes

* run-test-distros.sh output cosmetics

contrib/dind/roles/dind-host/tasks/main.yaml

@@ -0,0 +1,86 @@
+- name: set_fact distro_setup
+  set_fact:
+    distro_setup: "{{ distro_settings[node_distro] }}"
+
+- name: set_fact other distro settings
+  set_fact:
+    distro_image: "{{ distro_setup['image'] }}"
+    distro_init: "{{ distro_setup['init'] }}"
+    distro_pid1_exe: "{{ distro_setup['pid1_exe'] }}"
+    distro_raw_setup: "{{ distro_setup['raw_setup'] }}"
+    distro_raw_setup_done: "{{ distro_setup['raw_setup_done'] }}"
+    distro_agetty_svc: "{{ distro_setup['agetty_svc'] }}"
+
+- name: Create dind node containers from "containers" inventory section
+  docker_container:
+    image: "{{ distro_image }}"
+    name: "{{ item }}"
+    state: started
+    hostname: "{{ item }}"
+    command: "{{ distro_init }}"
+    #recreate: yes
+    privileged: true
+    tmpfs:
+      - /sys/module/nf_conntrack/parameters
+    volumes:
+      - /boot:/boot
+      - /lib/modules:/lib/modules
+      - "{{ item }}:/dind/docker"
+  register: containers
+  with_items: "{{groups.containers}}"
+  tags:
+    - addresses
+
+- name: Gather list of containers IPs
+  set_fact:
+    addresses: "{{ containers.results | map(attribute='ansible_facts') | map(attribute='docker_container') | map(attribute='NetworkSettings') | map(attribute='IPAddress') | list }}"
+  tags:
+    - addresses
+
+- name: Create inventory_builder helper already set with the list of node containers' IPs
+  template:
+    src: inventory_builder.sh.j2
+    dest: /tmp/kubespray.dind.inventory_builder.sh
+    mode: 0755
+  tags:
+    - addresses
+
+- name: Install needed packages into node containers via raw, need to wait for possible systemd packages to finish installing
+  raw: |
+    # agetty processes churn a lot of cpu time failing on inexistent ttys, early STOP them, to rip them in below task
+    pkill -STOP agetty || true
+    {{ distro_raw_setup_done }}  && echo SKIPPED && exit 0
+    until [ "$(readlink /proc/1/exe)" = "{{ distro_pid1_exe }}" ] ; do sleep 1; done
+    {{ distro_raw_setup }}
+  delegate_to: "{{ item._ansible_item_label }}"
+  with_items: "{{ containers.results }}"
+  register: result
+  changed_when: result.stdout.find("SKIPPED") < 0
+
+- name: Remove gettys from node containers
+  raw: |
+    until test -S /var/run/dbus/system_bus_socket; do sleep 1; done
+    systemctl disable {{ distro_agetty_svc }}
+    systemctl stop {{ distro_agetty_svc }}
+  delegate_to: "{{ item._ansible_item_label }}"
+  with_items: "{{ containers.results }}"
+  changed_when: false
+
+# Running systemd-machine-id-setup doesn't create a unique id for each node container on Debian,
+# handle manually
+- name: Re-create unique machine-id (as we may just get what comes in the docker image), needed by some CNIs for mac address seeding (notably weave)
+  raw: |
+    echo {{ item | hash('sha1') }} > /etc/machine-id.new
+    mv -b /etc/machine-id.new /etc/machine-id
+    cmp /etc/machine-id /etc/machine-id~ || true
+    systemctl daemon-reload
+  delegate_to: "{{ item._ansible_item_label }}"
+  with_items: "{{ containers.results }}"
+
+- name: Early hack image install to adapt for DIND
+  raw: |
+    rm -fv /usr/bin/udevadm /usr/sbin/udevadm
+  delegate_to: "{{ item._ansible_item_label }}"
+  with_items: "{{ containers.results }}"
+  register: result
+  changed_when: result.stdout.find("removed") >= 0

contrib/dind/roles/dind-host/templates/inventory_builder.sh.j2

@@ -0,0 +1,3 @@
+#!/bin/bash
+# NOTE: if you change HOST_PREFIX, you also need to edit ./hosts [containers] section
+HOST_PREFIX=kube-node python3 contrib/inventory_builder/inventory.py {% for ip in addresses %} {{ ip }} {% endfor %}