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