138 lines
6.6 KiB
Markdown
138 lines
6.6 KiB
Markdown
# Getting started
|
|
|
|
## Building your own inventory
|
|
|
|
Ansible inventory can be stored in 3 formats: YAML, JSON, or INI-like. There is
|
|
an example inventory located
|
|
[here](https://github.com/kubernetes-sigs/kubespray/blob/master/inventory/sample/inventory.ini).
|
|
|
|
You can use an
|
|
[inventory generator](https://github.com/kubernetes-sigs/kubespray/blob/master/contrib/inventory_builder/inventory.py)
|
|
to create or modify an Ansible inventory. Currently, it is limited in
|
|
functionality and is only used for configuring a basic Kubespray cluster inventory, but it does
|
|
support creating inventory file for large clusters as well. It now supports
|
|
separated ETCD and Kubernetes master roles from node role if the size exceeds a
|
|
certain threshold. Run `python3 contrib/inventory_builder/inventory.py help` help for more information.
|
|
|
|
Example inventory generator usage:
|
|
|
|
```ShellSession
|
|
cp -r inventory/sample inventory/mycluster
|
|
declare -a IPS=(10.10.1.3 10.10.1.4 10.10.1.5)
|
|
CONFIG_FILE=inventory/mycluster/hosts.yml python3 contrib/inventory_builder/inventory.py ${IPS[@]}
|
|
```
|
|
|
|
Then use `inventory/mycluster/hosts.yml` as inventory file.
|
|
|
|
## Starting custom deployment
|
|
|
|
Once you have an inventory, you may want to customize deployment data vars
|
|
and start the deployment:
|
|
|
|
**IMPORTANT**: Edit my\_inventory/groups\_vars/\*.yaml to override data vars:
|
|
|
|
```ShellSession
|
|
ansible-playbook -i inventory/mycluster/hosts.yml cluster.yml -b -v \
|
|
--private-key=~/.ssh/private_key
|
|
```
|
|
|
|
See more details in the [ansible guide](docs/ansible.md).
|
|
|
|
### Adding nodes
|
|
|
|
You may want to add worker, master or etcd nodes to your existing cluster. This can be done by re-running the `cluster.yml` playbook, or you can target the bare minimum needed to get kubelet installed on the worker and talking to your masters. This is especially helpful when doing something like autoscaling your clusters.
|
|
|
|
- Add the new worker node to your inventory in the appropriate group (or utilize a [dynamic inventory](https://docs.ansible.com/ansible/intro_dynamic_inventory.html)).
|
|
- Run the ansible-playbook command, substituting `cluster.yml` for `scale.yml`:
|
|
|
|
```ShellSession
|
|
ansible-playbook -i inventory/mycluster/hosts.yml scale.yml -b -v \
|
|
--private-key=~/.ssh/private_key
|
|
```
|
|
|
|
### Remove nodes
|
|
|
|
You may want to remove **master**, **worker**, or **etcd** nodes from your
|
|
existing cluster. This can be done by re-running the `remove-node.yml`
|
|
playbook. First, all specified nodes will be drained, then stop some
|
|
kubernetes services and delete some certificates,
|
|
and finally execute the kubectl command to delete these nodes.
|
|
This can be combined with the add node function. This is generally helpful
|
|
when doing something like autoscaling your clusters. Of course, if a node
|
|
is not working, you can remove the node and install it again.
|
|
|
|
Use `--extra-vars "node=<nodename>,<nodename2>"` to select the node(s) you want to delete.
|
|
|
|
```ShellSession
|
|
ansible-playbook -i inventory/mycluster/hosts.yml remove-node.yml -b -v \
|
|
--private-key=~/.ssh/private_key \
|
|
--extra-vars "node=nodename,nodename2"
|
|
```
|
|
|
|
If a node is completely unreachable by ssh, add `--extra-vars reset_nodes=no`
|
|
to skip the node reset step. If one node is unavailable, but others you wish
|
|
to remove are able to connect via SSH, you could set reset_nodes=no as a host
|
|
var in inventory.
|
|
|
|
## Connecting to Kubernetes
|
|
|
|
By default, Kubespray configures kube-master hosts with insecure access to
|
|
kube-apiserver via port 8080. A kubeconfig file is not necessary in this case,
|
|
because kubectl will use <http://localhost:8080> to connect. The kubeconfig files
|
|
generated will point to localhost (on kube-masters) and kube-node hosts will
|
|
connect either to a localhost nginx proxy or to a loadbalancer if configured.
|
|
More details on this process are in the [HA guide](docs/ha-mode.md).
|
|
|
|
Kubespray permits connecting to the cluster remotely on any IP of any
|
|
kube-master host on port 6443 by default. However, this requires
|
|
authentication. One can get a kubeconfig from kube-master hosts
|
|
(see [below](#accessing-kubernetes-api)) or connect with a [username and password](vars.md#user-accounts).
|
|
|
|
For more information on kubeconfig and accessing a Kubernetes cluster, refer to
|
|
the Kubernetes [documentation](https://kubernetes.io/docs/tasks/access-application-cluster/configure-access-multiple-clusters/).
|
|
|
|
## Accessing Kubernetes Dashboard
|
|
|
|
Supported version is kubernetes-dashboard v2.0.x :
|
|
|
|
- Login options are : token/kubeconfig by default, basic can be enabled with `kube_basic_auth: true` inventory variable - not recommended because this requires ABAC api-server which is not tested by kubespray team
|
|
- Deployed by default in "kube-system" namespace, can be overriden with `dashboard_namespace: kubernetes-dashboard` in inventory,
|
|
- Only serves over https
|
|
|
|
Access is described in [dashboard docs](https://github.com/kubernetes/dashboard/blob/master/docs/user/accessing-dashboard/1.7.x-and-above.md). With kubespray's default deployment in kube-system namespace, instead of kuberntes-dashboard :
|
|
|
|
- Proxy URL is <http://localhost:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/#/login>
|
|
- kubectl commands must be run with "-n kube-system"
|
|
|
|
Accessing through Ingress is highly recommended. For proxy access, please note that proxy must listen to [localhost](https://github.com/kubernetes/dashboard/issues/692#issuecomment-220492484) (`proxy --address="x.x.x.x"` will not work)
|
|
|
|
For token authentication, guide to create Service Account is provided in [dashboard sample user](https://github.com/kubernetes/dashboard/blob/master/docs/user/access-control/creating-sample-user.md) doc. Still take care of default namespace.
|
|
|
|
Access can also by achieved via ssh tunnel on a master :
|
|
|
|
```bash
|
|
# localhost:8081 will be sent to master-1's own localhost:8081
|
|
ssh -L8001:localhost:8001 user@master-1
|
|
sudo -i
|
|
kubectl proxy
|
|
```
|
|
|
|
## Accessing Kubernetes API
|
|
|
|
The main client of Kubernetes is `kubectl`. It is installed on each kube-master
|
|
host and can optionally be configured on your ansible host by setting
|
|
`kubectl_localhost: true` and `kubeconfig_localhost: true` in the configuration:
|
|
|
|
- If `kubectl_localhost` enabled, `kubectl` will download onto `/usr/local/bin/` and setup with bash completion. A helper script `inventory/mycluster/artifacts/kubectl.sh` also created for setup with below `admin.conf`.
|
|
- If `kubeconfig_localhost` enabled `admin.conf` will appear in the `inventory/mycluster/artifacts/` directory after deployment.
|
|
- The location where these files are downloaded to can be configured via the `artifacts_dir` variable.
|
|
|
|
You can see a list of nodes by running the following commands:
|
|
|
|
```ShellSession
|
|
cd inventory/mycluster/artifacts
|
|
./kubectl.sh get nodes
|
|
```
|
|
|
|
If desired, copy admin.conf to ~/.kube/config.
|