133 lines
6.4 KiB
Markdown
133 lines
6.4 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` 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](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=no`
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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=no 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](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 could generate a kubeconfig based on one installed
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kube-master hosts (needs improvement) or connect with a username and password.
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By default, a user with admin rights is created, named `kube`.
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The password can be viewed after deployment by looking at the file
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`{{ credentials_dir }}/kube_user.creds` (`credentials_dir` is set to `{{ inventory_dir }}/credentials` by default). This contains a randomly generated
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password. If you wish to set your own password, just precreate/modify this
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file yourself.
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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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As of kubernetes-dashboard v1.7.x:
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- New login options that use apiserver auth proxying of token/basic/kubeconfig by default
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- Requires RBAC in authorization\_modes
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- Only serves over https
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- No longer available at <https://first_master:6443/ui> until apiserver is updated with the https proxy URL
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If the variable `dashboard_enabled` is set (default is true), then you can access the Kubernetes Dashboard at the following URL, You will be prompted for credentials:
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<https://first_master:6443/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/#!/login>
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Or you can run 'kubectl proxy' from your local machine to access dashboard in your browser from:
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<http://localhost:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/#!/login>
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It is recommended to access dashboard from behind a gateway (like Ingress Controller) that enforces an authentication token. Details and other access options here: <https://github.com/kubernetes/dashboard/wiki/Accessing-Dashboard---1.7.X-and-above>
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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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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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