部署生产级的 Kubernetes 集群,使用kubespray

2018/09/21 22:45
阅读数 1.8K

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部署生产级的 Kubernetes 集群,使用kubespray

欢迎加入 kubernetes slack, channel #kubespray. 获得邀请从这里 here

  • 可以部署到 AWS, GCE, Azure, OpenStack, vSphere, Oracle Cloud Infrastructure (Experimental), 或 Baremetal
  • Highly available cluster
  • Composable (Choice of the network plugin for instance)
  • Supports most popular Linux distributions
  • Continuous integration tests

快速开始

To deploy the cluster you can use :

Ansible

# Install dependencies from ``requirements.txt``
sudo pip install -r requirements.txt

# Copy ``inventory/sample`` as ``inventory/mycluster``
cp -rfp inventory/sample/* inventory/mycluster

# Update Ansible inventory file with inventory builder
declare -a IPS=(10.10.1.3 10.10.1.4 10.10.1.5)
CONFIG_FILE=inventory/mycluster/hosts.ini python3 contrib/inventory_builder/inventory.py ${IPS[@]}

# Review and change parameters under ``inventory/mycluster/group_vars``
cat inventory/mycluster/group_vars/all.yml
cat inventory/mycluster/group_vars/k8s-cluster.yml

# Deploy Kubespray with Ansible Playbook
ansible-playbook -i inventory/mycluster/hosts.ini cluster.yml

Note: When Ansible is already installed via system packages on the control machine, other python packages installed via sudo pip install -r requirements.txt will go to a different directory tree (e.g. /usr/local/lib/python2.7/dist-packages on Ubuntu) from Ansible's (e.g. /usr/lib/python2.7/dist-packages/ansible still on Ubuntu). As a consequence, ansible-playbook command will fail with:

ERROR! no action detected in task. This often indicates a misspelled module name, or incorrect module path.

probably pointing on a task depending on a module present in requirements.txt (i.e. "unseal vault").

One way of solving this would be to uninstall the Ansible package and then, to install it via pip but it is not always possible. A workaround consists of setting ANSIBLE_LIBRARY and ANSIBLE_MODULE_UTILS environment variables respectively to the ansible/modules and ansible/module_utils subdirectories of pip packages installation location, which can be found in the Location field of the output of pip show [package] before executing ansible-playbook.

Vagrant

For Vagrant we need to install python dependencies for provisioning tasks. Check if Python and pip are installed:

python -V && pip -V

If this returns the version of the software, you're good to go. If not, download and install Python from here https://www.python.org/downloads/source/ Install the necessary requirements

sudo pip install -r requirements.txt
vagrant up

Documents

Supported Linux Distributions

  • Container Linux by CoreOS
  • Debian Jessie, Stretch, Wheezy
  • Ubuntu 16.04, 18.04
  • CentOS/RHEL 7
  • Fedora 28
  • Fedora/CentOS Atomic
  • openSUSE Leap 42.3/Tumbleweed

Note: Upstart/SysV init based OS types are not supported.

Supported Components

Note: kubernetes doesn't support newer docker versions ("Version 17.03 is recommended... Versions 17.06+ might work, but have not yet been tested and verified by the Kubernetes node team" cf. Bootstrapping Clusters with kubeadm). Among other things kubelet currently breaks on docker's non-standard version numbering (it no longer uses semantic versioning). To ensure auto-updates don't break your cluster look into e.g. yum versionlock plugin or apt pin).

Note 2: rkt support as docker alternative is limited to control plane (etcd and kubelet). Docker is still used for Kubernetes cluster workloads and network plugins' related OS services. Also note, only one of the supported network plugins can be deployed for a given single cluster.

Requirements

  • Ansible v2.4 (or newer) and python-netaddr is installed on the machine that will run Ansible commands
  • Jinja 2.9 (or newer) is required to run the Ansible Playbooks
  • The target servers must have access to the Internet in order to pull docker images.
  • The target servers are configured to allow IPv4 forwarding.
  • Your ssh key must be copied to all the servers part of your inventory.
  • The firewalls are not managed, you'll need to implement your own rules the way you used to. in order to avoid any issue during deployment you should disable your firewall.
  • If kubespray is ran from non-root user account, correct privilege escalation method should be configured in the target servers. Then the ansible_become flag or command parameters --become or -b should be specified.

Network Plugins

You can choose between 6 network plugins. (default: calico, except Vagrant uses flannel)

  • flannel: gre/vxlan (layer 2) networking.

  • calico: bgp (layer 3) networking.

  • canal: a composition of calico and flannel plugins.

  • cilium: layer 3/4 networking (as well as layer 7 to protect and secure application protocols), supports dynamic insertion of BPF bytecode into the Linux kernel to implement security services, networking and visibility logic.

  • contiv: supports vlan, vxlan, bgp and Cisco SDN networking. This plugin is able to apply firewall policies, segregate containers in multiple network and bridging pods onto physical networks.

  • weave: Weave is a lightweight container overlay network that doesn't require an external K/V database cluster. (Please refer to weave troubleshooting documentation).

The choice is defined with the variable kube_network_plugin. There is also an option to leverage built-in cloud provider networking instead. See also Network checker.

Community docs and resources

Tools and projects on top of Kubespray

CI Tests

CI/end-to-end tests sponsored by Google (GCE) See the test matrix for details.

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