102fb94524
* Add note about changing private IP in admin.conf. When I run kubespray, a load balancer is created which should be used instead of the ip of the controller node. * Procedure to find load balancer and update admin.conf When I run kubespray, a load balancer is used instead of the private ip of the controller.
144 lines
6.8 KiB
Markdown
144 lines
6.8 KiB
Markdown
# Getting started
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## Building your own inventory
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Ansible inventory can be stored in 3 formats: YAML, JSON, or INI-like. There is
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an example inventory located
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[here](https://github.com/kubernetes-sigs/kubespray/blob/master/inventory/sample/inventory.ini).
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You can use an
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[inventory generator](https://github.com/kubernetes-sigs/kubespray/blob/master/contrib/inventory_builder/inventory.py)
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to create or modify an Ansible inventory. Currently, it is limited in
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functionality and is only used for configuring a basic Kubespray cluster inventory, but it does
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support creating inventory file for large clusters as well. It now supports
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separated ETCD and Kubernetes master roles from node role if the size exceeds a
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certain threshold. Run `python3 contrib/inventory_builder/inventory.py help` for more information.
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Example inventory generator usage:
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```ShellSession
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cp -r inventory/sample inventory/mycluster
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declare -a IPS=(10.10.1.3 10.10.1.4 10.10.1.5)
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CONFIG_FILE=inventory/mycluster/hosts.yml python3 contrib/inventory_builder/inventory.py ${IPS[@]}
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```
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Then use `inventory/mycluster/hosts.yml` as inventory file.
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## Starting custom deployment
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Once you have an inventory, you may want to customize deployment data vars
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and start the deployment:
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**IMPORTANT**: Edit my\_inventory/groups\_vars/\*.yaml to override data vars:
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```ShellSession
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ansible-playbook -i inventory/mycluster/hosts.yml cluster.yml -b -v \
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--private-key=~/.ssh/private_key
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```
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See more details in the [ansible guide](/docs/ansible.md).
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### Adding nodes
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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.
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- 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)).
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- Run the ansible-playbook command, substituting `cluster.yml` for `scale.yml`:
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```ShellSession
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ansible-playbook -i inventory/mycluster/hosts.yml scale.yml -b -v \
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--private-key=~/.ssh/private_key
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```
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### Remove nodes
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You may want to remove **master**, **worker**, or **etcd** nodes from your
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existing cluster. This can be done by re-running the `remove-node.yml`
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playbook. First, all specified nodes will be drained, then stop some
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kubernetes services and delete some certificates,
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and finally execute the kubectl command to delete these nodes.
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This can be combined with the add node function. This is generally helpful
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when doing something like autoscaling your clusters. Of course, if a node
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is not working, you can remove the node and install it again.
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Use `--extra-vars "node=<nodename>,<nodename2>"` to select the node(s) you want to delete.
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```ShellSession
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ansible-playbook -i inventory/mycluster/hosts.yml remove-node.yml -b -v \
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--private-key=~/.ssh/private_key \
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--extra-vars "node=nodename,nodename2"
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```
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If a node is completely unreachable by ssh, add `--extra-vars reset_nodes=false`
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to skip the node reset step. If one node is unavailable, but others you wish
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to remove are able to connect via SSH, you could set `reset_nodes=false` as a host
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var in inventory.
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## Connecting to Kubernetes
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By default, Kubespray configures kube-master hosts with insecure access to
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kube-apiserver via port 8080. A kubeconfig file is not necessary in this case,
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because kubectl will use <http://localhost:8080> to connect. The kubeconfig files
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generated will point to localhost (on kube-masters) and kube-node hosts will
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connect either to a localhost nginx proxy or to a loadbalancer if configured.
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More details on this process are in the [HA guide](/docs/ha-mode.md).
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Kubespray permits connecting to the cluster remotely on any IP of any
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kube-master host on port 6443 by default. However, this requires
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authentication. One can get a kubeconfig from kube-master hosts
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(see [below](#accessing-kubernetes-api)) or connect with a [username and password](/docs/vars.md#user-accounts).
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For more information on kubeconfig and accessing a Kubernetes cluster, refer to
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the Kubernetes [documentation](https://kubernetes.io/docs/tasks/access-application-cluster/configure-access-multiple-clusters/).
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## Accessing Kubernetes Dashboard
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Supported version is kubernetes-dashboard v2.0.x :
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- Login option : token/kubeconfig by default
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- Deployed by default in "kube-system" namespace, can be overridden with `dashboard_namespace: kubernetes-dashboard` in inventory,
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- Only serves over https
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Access is described in [dashboard docs](https://github.com/kubernetes/dashboard/tree/master/docs/user/accessing-dashboard). With kubespray's default deployment in kube-system namespace, instead of kuberntes-dashboard :
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- Proxy URL is <http://localhost:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/#/login>
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- kubectl commands must be run with "-n kube-system"
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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)
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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.
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Access can also by achieved via ssh tunnel on a master :
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```bash
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# localhost:8081 will be sent to master-1's own localhost:8081
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ssh -L8001:localhost:8001 user@master-1
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sudo -i
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kubectl proxy
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```
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## Accessing Kubernetes API
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The main client of Kubernetes is `kubectl`. It is installed on each kube-master
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host and can optionally be configured on your ansible host by setting
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`kubectl_localhost: true` and `kubeconfig_localhost: true` in the configuration:
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- 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`.
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- If `kubeconfig_localhost` enabled `admin.conf` will appear in the `inventory/mycluster/artifacts/` directory after deployment.
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- The location where these files are downloaded to can be configured via the `artifacts_dir` variable.
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NOTE: The controller host name in the admin.conf file might be a private IP. If so, change it to use the controller's public IP or the cluster's load balancer.
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You can see a list of nodes by running the following commands:
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```ShellSession
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cd inventory/mycluster/artifacts
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./kubectl.sh get nodes
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```
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If desired, copy admin.conf to ~/.kube/config.
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## Setting up your first cluster
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[Setting up your first cluster](/docs/setting-up-your-first-cluster.md) is an
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applied step-by-step guide for setting up your first cluster with Kubespray.
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