c12s-kubespray/contrib/dind/README.md
JuanJo Ciarlante 4077934519 [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
2018-10-15 09:44:02 +02:00

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Markdown

# Kubespray DIND experimental setup
This ansible playbook creates local docker containers
to serve as Kubernetes "nodes", which in turn will run
"normal" Kubernetes docker containers, a mode usually
called DIND (Docker-IN-Docker).
The playbook has two roles:
- dind-host: creates the "nodes" as containers in localhost, with
appropiate settings for DIND (privileged, volume mapping for dind
storage, etc).
- dind-cluster: customizes each node container to have required
system packages installed, and some utils (swapoff, lsattr)
symlinked to /bin/true to ease mimicking a real node.
This playbook has been test with Ubuntu 16.04 as host and ubuntu:16.04
as docker images (note that dind-cluster has specific customization
for these images).
The playbook also creates a `/tmp/kubespray.dind.inventory_builder.sh`
helper (wraps up running `contrib/inventory_builder/inventory.py` with
node containers IPs and prefix).
## Deploying
See below for a complete successful run:
1. Create the node containers
~~~~
# From the kubespray root dir
cd contrib/dind
pip install -r requirements.txt
ansible-playbook -i hosts dind-cluster.yaml
# Back to kubespray root
cd ../..
~~~~
NOTE: if the playbook run fails with something like below error
message, you may need to specifically set `ansible_python_interpreter`,
see `./hosts` file for an example expanded localhost entry.
~~~
failed: [localhost] (item=kube-node1) => {"changed": false, "item": "kube-node1", "msg": "Failed to import docker or docker-py - No module named requests.exceptions. Try `pip install docker` or `pip install docker-py` (Python 2.6)"}
~~~
2. Customize kubespray-dind.yaml
Note that there's coupling between above created node containers
and `kubespray-dind.yaml` settings, in particular regarding selected `node_distro`
(as set in `group_vars/all/all.yaml`), and docker settings.
~~~
$EDITOR contrib/dind/kubespray-dind.yaml
~~~
3. Prepare the inventory and run the playbook
~~~
INVENTORY_DIR=inventory/local-dind
mkdir -p ${INVENTORY_DIR}
rm -f ${INVENTORY_DIR}/hosts.ini
CONFIG_FILE=${INVENTORY_DIR}/hosts.ini /tmp/kubespray.dind.inventory_builder.sh
ansible-playbook --become -e ansible_ssh_user=debian -i ${INVENTORY_DIR}/hosts.ini cluster.yml --extra-vars @contrib/dind/kubespray-dind.yaml
~~~
NOTE: You could also test other distros without editing files by
passing `--extra-vars` as per below commandline,
replacing `DISTRO` by either `debian`, `ubuntu`, `centos`, `fedora`:
~~~
cd contrib/dind
ansible-playbook -i hosts dind-cluster.yaml --extra-vars node_distro=DISTRO
cd ../..
CONFIG_FILE=inventory/local-dind/hosts.ini /tmp/kubespray.dind.inventory_builder.sh
ansible-playbook --become -e ansible_ssh_user=DISTRO -i inventory/local-dind/hosts.ini cluster.yml --extra-vars @contrib/dind/kubespray-dind.yaml --extra-vars bootstrap_os=DISTRO
~~~
## Resulting deployment
See below to get an idea on how a completed deployment looks like,
from the host where you ran kubespray playbooks.
### node_distro: debian
Running from an Ubuntu Xenial host:
~~~
$ uname -a
Linux ip-xx-xx-xx-xx 4.4.0-1069-aws #79-Ubuntu SMP Mon Sep 24
15:01:41 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
1835dd183b75 debian:9.5 "sh -c 'apt-get -qy …" 43 minutes ago Up 43 minutes kube-node5
30b0af8d2924 debian:9.5 "sh -c 'apt-get -qy …" 43 minutes ago Up 43 minutes kube-node4
3e0d1510c62f debian:9.5 "sh -c 'apt-get -qy …" 43 minutes ago Up 43 minutes kube-node3
738993566f94 debian:9.5 "sh -c 'apt-get -qy …" 44 minutes ago Up 44 minutes kube-node2
c581ef662ed2 debian:9.5 "sh -c 'apt-get -qy …" 44 minutes ago Up 44 minutes kube-node1
$ docker exec kube-node1 kubectl get node
NAME STATUS ROLES AGE VERSION
kube-node1 Ready master,node 18m v1.12.1
kube-node2 Ready master,node 17m v1.12.1
kube-node3 Ready node 17m v1.12.1
kube-node4 Ready node 17m v1.12.1
kube-node5 Ready node 17m v1.12.1
$ docker exec kube-node1 kubectl get pod --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
default netchecker-agent-67489 1/1 Running 0 2m51s
default netchecker-agent-6qq6s 1/1 Running 0 2m51s
default netchecker-agent-fsw92 1/1 Running 0 2m51s
default netchecker-agent-fw6tl 1/1 Running 0 2m51s
default netchecker-agent-hostnet-8f2zb 1/1 Running 0 3m
default netchecker-agent-hostnet-gq7ml 1/1 Running 0 3m
default netchecker-agent-hostnet-jfkgv 1/1 Running 0 3m
default netchecker-agent-hostnet-kwfwx 1/1 Running 0 3m
default netchecker-agent-hostnet-r46nm 1/1 Running 0 3m
default netchecker-agent-lxdrn 1/1 Running 0 2m51s
default netchecker-server-864bd4c897-9vstl 1/1 Running 0 2m40s
default sh-68fcc6db45-qf55h 1/1 Running 1 12m
kube-system coredns-7598f59475-6vknq 1/1 Running 0 14m
kube-system coredns-7598f59475-l5q5x 1/1 Running 0 14m
kube-system kube-apiserver-kube-node1 1/1 Running 0 17m
kube-system kube-apiserver-kube-node2 1/1 Running 0 18m
kube-system kube-controller-manager-kube-node1 1/1 Running 0 18m
kube-system kube-controller-manager-kube-node2 1/1 Running 0 18m
kube-system kube-proxy-5xx9d 1/1 Running 0 17m
kube-system kube-proxy-cdqq4 1/1 Running 0 17m
kube-system kube-proxy-n64ls 1/1 Running 0 17m
kube-system kube-proxy-pswmj 1/1 Running 0 18m
kube-system kube-proxy-x89qw 1/1 Running 0 18m
kube-system kube-scheduler-kube-node1 1/1 Running 4 17m
kube-system kube-scheduler-kube-node2 1/1 Running 4 18m
kube-system kubernetes-dashboard-5db4d9f45f-548rl 1/1 Running 0 14m
kube-system nginx-proxy-kube-node3 1/1 Running 4 17m
kube-system nginx-proxy-kube-node4 1/1 Running 4 17m
kube-system nginx-proxy-kube-node5 1/1 Running 4 17m
kube-system weave-net-42bfr 2/2 Running 0 16m
kube-system weave-net-6gt8m 2/2 Running 0 16m
kube-system weave-net-88nnc 2/2 Running 0 16m
kube-system weave-net-shckr 2/2 Running 0 16m
kube-system weave-net-xr46t 2/2 Running 0 16m
$ docker exec kube-node1 curl -s http://localhost:31081/api/v1/connectivity_check
{"Message":"All 10 pods successfully reported back to the server","Absent":null,"Outdated":null}
~~~