kubectl
usage examplesThese scripts handle the creation, deletion and expansion of kubernetes clusters on CenturyLink Cloud.
You can accomplish all these tasks with a single command. We have made the Ansible playbooks used to perform these tasks available here.
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
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.
1) Clone this repository and cd into it.
git clone https://github.com/CenturyLinkCloud/adm-kubernetes-on-clc
2) Install all requirements, including * Ansible * CenturyLink Cloud SDK * Ansible Modules
sudo pip install -r ansible/requirements.txt
3) 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
4) Grant your machine access to the CenturyLink Cloud network by using a VM inside the network or configuring a VPN connection to the CenturyLink Cloud network.
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.
CLC_CLUSTER_NAME=[name of kubernetes cluster]
cd ./adm-kubernetes-on-clc
bash kube-up.sh -c="$CLC_CLUSTER_NAME"
It takes about 15 minutes to create the cluster. Once the script completes, it will output some commands that will help you setup kubectl on your machine to point to the new cluster.
When the cluster creation is complete, the configuration files for it are stored locally on your administrative host, in the following directory
> CLC_CLUSTER_HOME=$HOME/.clc_kube/$CLC_CLUSTER_NAME/
Usage: kube-up.sh [OPTIONS]
Create servers in the CenturyLinkCloud environment and initialize a Kubernetes cluster
Environment variables CLC_V2_API_USERNAME and CLC_V2_API_PASSWD must be set in
order to access the CenturyLinkCloud API
All options (both short and long form) require arguments, and must include "="
between option name and option value.
-h (--help) display this help and exit
-c= (--clc_cluster_name=) set the name of the cluster, as used in CLC group names
-t= (--minion_type=) standard -> VM (default), bareMetal -> physical]
-d= (--datacenter=) VA1 (default)
-m= (--minion_count=) number of kubernetes minion nodes
-mem= (--vm_memory=) number of GB ram for each minion
-cpu= (--vm_cpu=) number of virtual cps for each minion node
-phyid= (--server_conf_id=) physical server configuration id, one of
physical_server_20_core_conf_id
physical_server_12_core_conf_id
physical_server_4_core_conf_id (default)
-etcd_separate_cluster=yes create a separate cluster of three etcd nodes,
otherwise run etcd on the master node
To expand an existing Kubernetes cluster, run the add-kube-node.sh
script. A complete list of script options and some examples are listed [below].
This script must be run from the same host that created the cluster (or a host
that has the cluster artifact files stored in ~/.clc_kube/$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:
1) Use our python script:
python delete_cluster.py --cluster=clc_cluster_name --datacenter=DC1
2) 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:
We use the following to create the kubernetes cluster:
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. For example, you may want to use any of the Kubernetes API client libraries to program against your Kubernetes cluster in the programming language of your choice.
To demostrate how to use these locally stored certificates, we provide the folowing example of using curl
to communicate to the master api server via https:
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 hostshosts/
: hosts files listing access information for the ansible playbookskube/
: kubectl
configuration files, and the basic-authentication password for admin access to the Kubernetes APIpki/
: public key infrastructure files enabling TLS communication in the clusterssh/
: SSH keys for root access to the hostskubectl
usage examplesThere 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
Then, you can 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.
These are the known items that don’t work on CenturyLink cloud but do work on other cloud providers:
At this time, there is no support services of the type LoadBalancer. We are actively working on this and hope to publish the changes sometime around April 2016.
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
Please see the Kubernetes docs for more details on administering and using a Kubernetes cluster.