c12s-kubespray/docs/ansible.md
Bogdan Dobrelya 32cd6e99b2 Add etcd proxy support
* Enforce a etcd-proxy role to a k8s-cluster group members. This
provides an HA layout for all of the k8s cluster internal clients.
* Proxies to be run on each node in the group as a separate etcd
instances with a readwrite proxy mode and listen the given endpoint,
which is either the access_ip:2379 or the localhost:2379.
* A notion for the 'kube_etcd_multiaccess' is: ignore endpoints and
loadbalancers and use the etcd members IPs as a comma-separated
list. Otherwise, clients shall use the local endpoint provided by a
etcd-proxy instances on each etcd node. A Netwroking plugins always
use that access mode.
* Fix apiserver's etcd servers args to use the etcd_access_endpoint.
* Fix networking plugins flannel/calico to use the etcd_endpoint.
* Fix name env var for non masters to be set as well.
* Fix etcd_client_url was not used anywhere and other etcd_* facts
evaluation was duplicated in a few places.
* Define proxy modes only in the env file, if not a master. Del
an automatic proxy mode decisions for etcd nodes in init/unit scripts.
* Use Wants= instead of Requires= as "This is the recommended way to
hook start-up of one unit to the start-up of another unit"
* Make apiserver/calico Wants= etcd-proxy to keep it always up

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
Co-authored-by: Matthew Mosesohn <mmosesohn@mirantis.com>
2016-07-19 14:09:40 +02:00

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Ansible variables
===============
Inventory
-------------
The inventory is composed of 3 groups:
* **kube-node** : list of kubernetes nodes where the pods will run.
* **kube-master** : list of servers where kubernetes master components (apiserver, scheduler, controller) will run.
Note: if you want the server to act both as master and node the server must be defined on both groups _kube-master_ and _kube-node_
* **etcd**: list of server to compose the etcd server. you should have at least 3 servers for failover purposes.
Below is a complete inventory example:
```
## Configure 'ip' variable to bind kubernetes services on a
## different ip than the default iface
node1 ansible_ssh_host=95.54.0.12 # ip=10.3.0.1
node2 ansible_ssh_host=95.54.0.13 # ip=10.3.0.2
node3 ansible_ssh_host=95.54.0.14 # ip=10.3.0.3
node4 ansible_ssh_host=95.54.0.15 # ip=10.3.0.4
node5 ansible_ssh_host=95.54.0.16 # ip=10.3.0.5
node6 ansible_ssh_host=95.54.0.17 # ip=10.3.0.6
[kube-master]
node1
node2
[etcd]
node1
node2
node3
[kube-node]
node2
node3
node4
node5
node6
[k8s-cluster:children]
kube-node
kube-master
etcd
```
Group vars
--------------
The main variables to change are located in the directory ```inventory/group_vars/all.yml```.