Kuberntes Cluster for UOS

To install

After deploy ssh key to nodes

ansible-playbook -i inventory/prod/hosts.yaml  --become --become-user=root cluster.yml

Assuming three nodes with IP addresses of 192.168.2.100, 192.168.2.101, and 192.168.2.102.

Things to know

1. Kubernetes v1.19.3
2. using containerd as a runtime.
3. using cilium as a CNI. (I believe cilium is the future! :-D)
4. can access to a apiserver with http://127.0.0.1:8080 (THIS IS NOT SECURED, AND IT IS INTENDED)
5. HELM, Dashboard, and MetalLB is installed by default.
6. MetalLB will be run as Layer 2 mode, and will use 192.168.2.240 ~ 192.168.2.250. So, MAKE SURE NO OTHER DEVICES USING THIS IP ADDRESSES
7. etcd will be deployed on hosts. (not containerized)
8. It takes some time for node fail-over. (max 10 min.)
9. the existing application will run fine until two of three nodes die.
10. If not all three nodes are not fully functional, you can not use kubectl

email me if you have any question. :-)

[email protected]

Deploy a Production Ready Kubernetes Cluster

If you have questions, check the documentation at kubespray.io and join us on the kubernetes slack, channel #kubespray. You can get your invite here

• Can be deployed on AWS, GCE, Azure, OpenStack, vSphere, Packet (bare metal), Oracle Cloud Infrastructure (Experimental), or Baremetal
• Highly available cluster
• Composable (Choice of the network plugin for instance)
• Supports most popular Linux distributions
• Continuous integration tests

Quick Start

To deploy the cluster you can use :

Ansible

Usage

# Install dependencies from ``requirements.txt``
sudo pip3 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.yaml python3 contrib/inventory_builder/inventory.py ${IPS[@]}

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

# Deploy Kubespray with Ansible Playbook - run the playbook as root
# The option `--become` is required, as for example writing SSL keys in /etc/,
# installing packages and interacting with various systemd daemons.
# Without --become the playbook will fail to run!
ansible-playbook -i inventory/mycluster/hosts.yaml  --become --become-user=root 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

• Requirements
• Kubespray vs ...
• Getting started
• Setting up your first cluster
• Ansible inventory and tags
• Integration with existing ansible repo
• Deployment data variables
• DNS stack
• HA mode
• Network plugins
• Vagrant install
• Flatcar Container Linux bootstrap
• Fedora CoreOS bootstrap
• Debian Jessie setup
• openSUSE setup
• Downloaded artifacts
• Cloud providers
• OpenStack
• AWS
• Azure
• vSphere
• Packet Host
• Large deployments
• Adding/replacing a node
• Upgrades basics
• Air-Gap installation
• Roadmap

Supported Linux Distributions

• Flatcar Container Linux by Kinvolk
• Debian Buster, Jessie, Stretch, Wheezy
• Ubuntu 16.04, 18.04, 20.04
• CentOS/RHEL 7, 8 (experimental: see centos 8 notes)
• Fedora 31, 32
• Fedora CoreOS (experimental: see fcos Note)
• openSUSE Leap 42.3/Tumbleweed
• Oracle Linux 7, 8 (experimental: centos 8 notes apply)

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

Supported Components

• Core
  • kubernetes v1.19.3
  • etcd v3.4.3
  • docker v19.03 (see note)
  • containerd v1.3.7
  • cri-o v1.19 (experimental: see CRI-O Note. Only on fedora, ubuntu and centos based OS)
• Network Plugin
  • cni-plugins v0.8.7
  • calico v3.16.5
  • canal (given calico/flannel versions)
  • cilium v1.8.5
  • flanneld v0.13.0
  • kube-ovn v1.5.2
  • kube-router v1.1.0
  • multus v3.6.0
  • ovn4nfv v1.1.0
  • weave v2.7.0
• Application
  • ambassador: v1.5
  • cephfs-provisioner v2.1.0-k8s1.11
  • rbd-provisioner v2.1.1-k8s1.11
  • cert-manager v0.16.1
  • coredns v1.7.0
  • ingress-nginx v0.40.2

Note: The list of validated docker versions is 1.13.1, 17.03, 17.06, 17.09, 18.06, 18.09 and 19.03. The recommended docker version is 19.03. The kubelet might break 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).

Requirements

• Minimum required version of Kubernetes is v1.17
• Ansible v2.9+, Jinja 2.11+ and python-netaddr is installed on the machine that will run Ansible commands
• The target servers must have access to the Internet in order to pull docker images. Otherwise, additional configuration is required (See Offline Environment)
• The target servers are configured to allow IPv4 forwarding.
• 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.

Hardware: These limits are safe guarded by Kubespray. Actual requirements for your workload can differ. For a sizing guide go to the Building Large Clusters guide.

• Master
  • Memory: 1500 MB
• Node
  • Memory: 1024 MB

Network Plugins

You can choose between 10 network plugins. (default: calico, except Vagrant uses flannel)

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

• Calico is a networking and network policy provider. Calico supports a flexible set of networking options designed to give you the most efficient networking across a range of situations, including non-overlay and overlay networks, with or without BGP. Calico uses the same engine to enforce network policy for hosts, pods, and (if using Istio and Envoy) applications at the service mesh layer.

• 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.

• ovn4nfv: ovn4nfv-k8s-plugins is the network controller, OVS agent and CNI server to offer basic SFC and OVN overlay networking.

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

• kube-ovn: Kube-OVN integrates the OVN-based Network Virtualization with Kubernetes. It offers an advanced Container Network Fabric for Enterprises.

• kube-router: Kube-router is a L3 CNI for Kubernetes networking aiming to provide operational simplicity and high performance: it uses IPVS to provide Kube Services Proxy (if setup to replace kube-proxy), iptables for network policies, and BGP for ods L3 networking (with optionally BGP peering with out-of-cluster BGP peers). It can also optionally advertise routes to Kubernetes cluster Pods CIDRs, ClusterIPs, ExternalIPs and LoadBalancerIPs.

• macvlan: Macvlan is a Linux network driver. Pods have their own unique Mac and Ip address, connected directly the physical (layer 2) network.

• multus: Multus is a meta CNI plugin that provides multiple network interface support to pods. For each interface Multus delegates CNI calls to secondary CNI plugins such as Calico, macvlan, etc.

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.

Ingress Plugins

• ambassador: the Ambassador Ingress Controller and API gateway.

• nginx: the NGINX Ingress Controller.

Community docs and resources

• kubernetes.io/docs/setup/production-environment/tools/kubespray/
• kubespray, monitoring and logging by @gregbkr
• Deploy Kubernetes w/ Ansible & Terraform by @rsmitty
• Deploy a Kubernetes Cluster with Kubespray (video)

Tools and projects on top of Kubespray

• Digital Rebar Provision
• Terraform Contrib

CI Tests

CI/end-to-end tests sponsored by: CNCF, Packet, OVHcloud, ELASTX.

See the test matrix for details.