These scripts handle the creation, deletion and expansion of kubernetes clusters on CenturyLink Cloud.
You can accomplish all these tasks with a simple single command. And, for those interested in what's under the covers, we used Ansible to perform these tasks and we have made these Ansible playbooks available as well.
If you run into any problems or want help with anything, we are here to help. Reach out to use via any of the following ways:
- Submit a github issue
- Send an email to kubernetes AT ctl DOT io
- Visit http://info.ctl.io/kubernetes
- We support Kubernetes clusters on both Virtual Machines or Physical Servers. If you want to use physical servers for the worker nodes (minions), simple use the --minion_type=bareMetal flag.
- For more information on physical servers, visit: https://www.ctl.io/bare-metal/)
- Physical serves are only available in the VA1 and GB3 data centers.
- VMs are available in all 13 of our public cloud locations
The requirements to run this script are:
- A linux administrative host (tested on ubuntu and OSX)
- python 2 (tested on 2.7.11)
- pip (installed with python as of 2.7.9)
- git
- A CenturyLink Cloud account with rights to create new hosts
- An active VPN connection to the CenturyLink Cloud from your linux host
After you have all the requirements met, please follow these instructions to install this script.
- Clone this repository and cd into it.
git clone https://github.com/CenturyLinkCloud/adm-kubernetes-on-clc
- Install all requirements, including
- Ansible
- CenturyLink Cloud SDK
- Ansible Modules
sudo pip install -r requirements.txt
- Create the credentials file from the template and use it to set your ENV variables
cp ansible/credentials.sh.template ansible/credentials.sh
vi ansible/credentials.sh
source ansible/credentials.sh
- Make sure the computer you are working on has access to the CenturyLink Cloud network. This is done by using a VM inside the CenturyLink Cloud network or having an active VPN connection to the CenturyLink Cloud network. To find out how to configure the VPN connection, visit here
If you use an ubuntu 14, for your convenience we have provided a step by step guide to install the requirements and install the script.
# system
apt-get update
apt-get install -y git python python-crypto
curl -O https://bootstrap.pypa.io/get-pip.py
python get-pip.py
# installing this repository
mkdir -p ~home/k8s-on-clc
cd ~home/k8s-on-clc
git clone https://github.com/CenturyLinkCloud/adm-kubernetes-on-clc.git
cd adm-kubernetes-on-clc/
pip install -r requirements.txt
# getting started
cd ansible
cp credentials.sh.template credentials.sh; vi credentials.sh
source credentials.sh
To create a new Kubernetes cluster, simply run the kube-up.sh script. A complete list of script options and some examples are listed below.
export CLC_CLUSTER_NAME=[name of kubernetes cluster]
cd ./adm-kubernetes-on-clc
bash kube-up.sh -c="$CLC_CLUSTER_NAME"
It takes about 15 minutes to create the cluster. Once the script completes, it will output some commands that will help you setup kubectl on your machine to point to the new cluster.
When the cluster creation is complete, the configuration files for it are stored locally on your administrative host, in the directory
CLC_CLUSTER_HOME=$HOME/.clc_kube/$CLC_CLUSTER_NAME/
Usage: kube-up.sh [OPTIONS]
Create servers in the CenturyLinkCloud environment and initialize a Kubernetes cluster
Environment variables CLC_V2_API_USERNAME and CLC_V2_API_PASSWD must be set in
order to access the CenturyLinkCloud API
All options (both short and long form) require arguments, and must include "="
between option name and option value.
-h (--help) display this help and exit
-c= (--clc_cluster_name=) set the name of the cluster, as used in CLC group names
-t= (--minion_type=) standard -> VM (default), bareMetal -> physical]
-d= (--datacenter=) VA1 (default)
-m= (--minion_count=) number of kubernetes minion nodes
-mem= (--vm_memory=) number of GB ram for each minion
-cpu= (--vm_cpu=) number of virtual cps for each minion node
-phyid= (--server_conf_id=) physical server configuration id, one of
physical_server_20_core_conf_id
physical_server_12_core_conf_id
physical_server_4_core_conf_id (default)
-etcd_separate_cluster=yes create a separate cluster of three etcd nodes,
otherwise run etcd on the master node
To expand an existing Kubernetes cluster, run the add-kube-node.sh script. A complete list of script options and some examples are listed below. This script must be run from the same hose that created the cluster (or a host that has the cluster artifact files stored in ~/.clc_kube/$cluster_name).
cd ./adm-kubernetes-on-clc
bash add-kube-node.sh -c="name_of_kubernetes_cluster" -m=2
Usage: add-kube-node.sh [OPTIONS]
Create servers in the CenturyLinkCloud environment and add to an
existing CLC kubernetes cluster
Environment variables CLC_V2_API_USERNAME and CLC_V2_API_PASSWD must be set in
order to access the CenturyLinkCloud API
-h (--help) display this help and exit
-c= (--clc_cluster_name=) set the name of the cluster, as used in CLC group names
-m= (--minion_count=) number of kubernetes minion nodes to add
There are two ways to delete an existing cluster:
- Use our python script:
python delete_cluster.py --clc_cluster_name=clc_cluster_name --datacenter=DC1
- Use the CenturyLink Cloud UI. To delete a cluster, log into the CenturyLink Cloud control portal and delete the parent server group that contains the Kubernetes Cluster. We hope to add a scripted option to do this soon.
Create a cluster with name of k8s_1, 1 master node and 3 worker minions (on physical machines), in VA1
bash kube-up.sh --clc_cluster_name=k8s_1 --minion_type=bareMetal --minion_count=3 --datacenter=VA1
Create a cluster with name of k8s_2, an ha etcd cluster on 3 VMs and 6 worker minions (on VMs), in VA1
bash kube-up.sh --clc_cluster_name=k8s_2 --minion_type=standard --minion_count=6 --datacenter=VA1 --etcd_separate_cluster=yes
Create a cluster with name of k8s_3, 1 master node, and 10 worker minions (on VMs) with higher mem/cpu, in UC1:
bash kube-up.sh --clc_cluster_name=k8s_3 --minion_type=standard --minion_count=10 --datacenter=VA1 -mem=6 -cpu=4
We configue the Kubernetes cluster with the following features:
- KubeDNS: DNS resolution and service discovery
- Heapster/InfluxDB: For metric collection. Needed for Grafana and auto-scaling.
- Grafana: Kubernetes/Docker metric dashboard
- KubeUI: Simple web interface to view kubernetes state
- Kube Dashboard: New web interface to interact with your cluster
We use the following to create the kubernetes cluster:
- Kubernetes 1.1.7
- Unbuntu 14.04
- Flannel 0.5.4
- Docker 1.9.1-0~trusty
- Etcd 2.2.2
- Logging: We offer an integrated centralized logging ELK platform so that all kubernetes and docker logs get sent to the ELK stack. To install the ELK stack and configure kubernetes to send logs to it, follow this documentation: log aggregation. Note: We don't install this by default as the footprint isn't trivial.
The most widely used tool for managing a kubernetes cluster is the command-line utility kubectl. If you do not already have a copy of this binary on your administrative machine, you may run the script install_kubectl.sh which will download it and install it in /usr/bin/local.
The script requires that the environment variable CLC_CLUSTER_NAME be defined
install_kubectl.sh also writes a configuration file which will embed the necessary authentication certificates for the particular cluster. The configuration file is written to the ${CLC_CLUSTER_HOME}/kube directory
export KUBECONFIG=${CLC_CLUSTER_HOME}/kube/config
kubectl version
kubectl cluster-info
It's possible to use the locally-stored client certificates to access the api server
curl \
--cacert ${CLC_CLUSTER_HOME}/pki/ca.crt \
--key ${CLC_CLUSTER_HOME}/pki/kubecfg.key \
--cert ${CLC_CLUSTER_HOME}/pki/kubecfg.crt https://${MASTER_IP}:6443
But please note, this does not work out of the box with the curl binary distributed with OSX
We install two UIs on kubernetes. The orginal KubeUI and the newer kube dashboard. When you create a cluster, the script should output URLs for these interfaces like this:
KubeUI is running at https://${MASTER_IP}:6443/api/v1/proxy/namespaces/kube-system/services/kube-ui kubernetes-dashboard is running at https://${MASTER_IP}:6443/api/v1/proxy/namespaces/kube-system/services/kubernetes-dashboard
Note on Authentication to the UIs: The cluster is set up to use basic authentication for the user admin. Hitting the url at https://${MASTER_IP}:6443 will require accepting the self-signed certificate from the apiserver, and then presenting the admin password written to file at
${CLC_CLUSTER_HOME}/kube/admin_password.txt
Various configuration files are written into the home directory CLC_CLUSTER_HOME under .clc_kube/${CLC_CLUSTER_NAME} in several subdirectories. You can use these files to access the cluster from machines other than where you created the cluster from.
- config/: ansible variable files containing parameters describing the master and minion hosts
- hosts/: hosts files listing access information for the ansible playbooks
- kube/: kubectl configuration files, and the basic-authentication password for admin access to the kubernetes api
- pki/: public key infrastructure files enabling TLS communication in the cluster
- ssh/: ssh keys for root access to the hosts
There are a great many features of kubectl. Here are a few examples
List existing nodes, pods, services and more, in all namespaces, or in just one
kubectl get nodes
kubectl get --all-namespaces services
kubectl get --namespace=kube-system replicationcontrollers
The kubernetes api server exposes services on web urls, which are protected by requiring client certificates. If you run a kubectl proxy locally, kubectl will provide the necessary certificates and serve locally over http.
kubectl proxy -p 8001
and then access urls like http://127.0.0.1:8001/api/v1/proxy/namespaces/kube-system/services/kube-ui/ without the need for client certificates in your browser.
- At this time, there is no support services of the type 'loadbalancer'. We are actively working on this and hope to publish the changes soon.
- At this time, there is no support for persistent storage volumes provided by CenturyLink Cloud. However, customers can bring their own persistent storage offering. We ourselves use Gluster.
If you want more information about our ansible files, please read this file
The project is licensed under the Apache License v2.0.