Introduction<\/h2>\n
One of the biggest challenges with Kubernetes is bringing up a cluster for the This is the problem that the people at Rancher are solving with the What this tutorial will show you is how to quickly set up a few virtual systems NOTE: This example will bring up a bare minimum cluster with a sample For our virtual cluster, we will be using Exoscale<\/a> In addition, you will need an Exoscale account<\/a> Once you have your Exoscale account set-up, you need to configure the Exoscale $ .\/exo config<\/p>\n Hi happy Exoscalian, some configuration is required to use exo.<\/p>\n We now need some very important information, find them there. [+] API Key [none]: EXO\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7 NOTE: When you go to the API profile page<\/a> Now that we have configured the Exoscale CLI, we need to prepare the Exoscale The firewall or security group we will create must have at least three The first step to this is to create the firewall or security group<\/em>:<\/p>\n $ .\/exo firewall create rke-k8s -d “RKE k8s SG” The next step is to add the rules (command output omitted):<\/p>\n $ .\/exo firewall add rke-k8s -p ALL -s rke-k8s You can confirm the results by invoking exo firewall show:<\/p>\n $ .\/exo firewall show rke-k8s One of the nice things about the Exoscale CLI is that you can use it to create If you have a key you want to use:<\/p>\n $ .\/exo sshkey upload [keyname] [ssh-public-key-path]<\/p>\n Or if you\u2019d like to create a unique for this cluster:<\/p>\n $ .\/exo sshkey create rke-k8s-key $<\/p>\n Save the contents of the RSA PRIVATE KEY component into a file as $ ssh-add [path-to-private-ssh-key]<\/p>\n At this point we are ready to create the instances. We will utilize the medium NOTE: If you go with a smaller instance size than medium, you will not Step 1: Create instance configuration script<\/p>\n To automate the instance configuration, we will use cloud-init<\/a>. #cloud-config<\/p>\n manage_etc_hosts: true<\/p>\n package_update: true packages: runcmd: power_state: Copy and paste the block of text above into a new file called cloud-init.yml.<\/p>\n Step 2: Create the instances<\/p>\n Next, we are going to create 4 instances:<\/p>\n $ for i in 1 2 3 4; do What to do now?<\/p>\n 1. Connect to the machine<\/p>\n > exo ssh rancher-1 2. Put the SSH configuration into “.ssh\/config”<\/p>\n > exo ssh rancher-1 –info Tip of the day: NOTE: If you created or uploaded an SSH Keypair, then you can add the NOTE 2: Save the hostname and IP address. You will need these for the RKE set-up<\/p><\/blockquote>\n After waiting several minutes (about 5 to be safe) you will have four brand new \u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c The Rancher Kubernetes Engine command is used to bring up, tear down, and The file below is a sample file that can be saved and modified as cluster.yml:<\/p>\n —<\/p>\n ssh_key_path: [path to ssh private key] cluster_name: rke-k8s<\/p>\n nodes: Things you will need to modify:<\/p>\n Once you have saved your updated cluster.yml, $ .\/rke up is all you need to If everything goes well, then you will see the following when RKE finishes:<\/p>\n $ rke up<\/p>\n …<\/p>\n INFO[0099] Finished building Kubernetes cluster successfully<\/p>\n Congratulations, you have just brought up a Kubernetes cluster!<\/p>\n One thing you will see that RKE created is the Kubernetes configuration file export KUBECONFIG=\/path\/to\/kube_config_cluster.yml<\/p>\n Here are a few sample status commands. The first command will give $ .\/kubectl get nodes The second command is used to give you the cluster status.<\/p>\n $ .\/kubectl get cs NOTE: For more information about RKE and the cluster configuration file, you can visit To make it easier to collect status information on the Kubernetes cluster, we $ .\/kubectl create -f https:\/\/raw.githubusercontent.com\/kubernetes\/dashboard\/master\/src\/deploy\/recommended\/kubernetes-dashboard.yaml<\/p>\n At this point, the dashboard is installed and running, but the only way to access Now you can now visit the dashboard at: However, to be able to make full use of the dashboard, you will need to $ .\/kubectl -n kube-system describe secrets Copy and paste the long string that is returned into the authentication prompt Now for the fun part. We are going to bring up Cassandra<\/a>. To install Cassandra, we need to specify a service configuration that will be First, we will start with the services file:<\/p>\n apiVersion: v1 Copy and save the services file as cassandra-services.yaml, and load it:<\/p>\n .\/kubectl create -f .\/cassandra-service.yml<\/p>\n You should see it load successfully, and you can verify using kubectl:<\/p>\n $ .\/kubectl get svc cassandra NOTE: For more details on Service configurations, you can read more about it in the The StatefulSet<\/a> We will download the configuration from XXXXX\/cassandra-statefulset.yaml, $ .\/kubectl create -f https:\/\/XXXX\/cassandra-statefulset.yaml You can check the state of the StatefulSet we are loading:<\/p>\n $ .\/kubectl get statefulset You can even interact with Cassandra inside its pod such as verifying that $ .\/kubectl exec -it cassandra-0 — nodetool status Now suppose we want to scale up the number of replicas from 3, to 4? To do that, you $ .\/kubectl edit statefulset cassandra<\/p>\n This will open up your default text editor. Scroll down to the replica line, $ .\/kubectl get statefulset $ .\/kubectl exec -it cassandra-0 — nodetool status There is one final note about cluster scaling and using the StatefulSet workload. And here are gists with the yaml configurations from this tutorial that might be helpful as well:<\/p>\n Chris Baumbauer<\/p>\n Software Engineer<\/p>\n Chris Baumbauer is a freelance engineer whom has dabbled every piece of the stack from operating systems to mobile and web development with recent projects focused on Kubernetes such as Kompose and Kmachine.<\/p>\n
\nfirst time. There have been several projects that attempt to address this gap
\nincluding kmachine<\/a> and
\nminikube<\/a>. However, both assume
\nyou are starting from a blank slate. What if you have your instances provisioned,
\nor have another means of provisioning hosts with configuration management?<\/p>\n
\nRancher Kubernetes Engine or RKE<\/a>.
\nAt the core is a YAML based configuration file that is used to define the hosts
\nand make-up for your Kubernetes cluster. RKE will do the heavy lifting of
\ninstalling the required Kubernetes components, and configuring them for your
\ncluster.<\/p>\n
\nthat can host our Kubernetes cluster, bring up Kubernetes
\nusing RKE, and lastly setup a sample application hosted inside Kubernetes.<\/p>\n
\napplication for experimentation, and in no way should be considered
\na production ready deployment.<\/p><\/blockquote>\nPrerequisites and Setup<\/h2>\n
\nas they will allow us to get up and running with minimal effort. There are three
\nbinaries that you will need to install to fully utilize this guide. While this
\nguide is written assuming Linux, the binaries are available for Linux, Windows,
\nand MacOS.<\/p>\n\n
\nsince it will be used to setup the Exoscale CLI.<\/p>\nConfigure Exoscale CLI<\/h3>\n
\nclient. Assuming you are in the same directory containing the program you will run:<\/p>\n
\n<https:\/\/portal.exoscale.com\/account\/profile\/api><\/p>\n
\n[+] Secret Key [none]: \u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7\u00b7
\n[…]<\/p>\n
\nyou will see the API Key and Secret. Be sure to copy and paste both at the prompts.<\/p><\/blockquote>\nProvisioning the Kubernetes Environment with the Exoscale CLI<\/h2>\n
\ncloud environment. This will require setting up a firewall rule that will be
\ninherited by the instances that will become the Kubernetes cluster, and an optional
\nstep of creating and adding your ssh public key.<\/p>\nDefining the firewall rules<\/h3>\n
\nports exposed: 22 for ssh access, 6443 and 10240 for kubectl and rke to bring up
\nand manage the cluster. Lastly, we need to grant access to the security group so
\nthe instances can interact amongst itself.<\/p>\n
\n\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c
\n\u2502 NAME \u2502 DESCRIPTION \u2502 ID \u2502
\n\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c
\n\u2502 rke-k8s \u2502 RKE K8S SG \u2502 01a3b13f-a312-449c-a4ce-4c0c68bda457 \u2502
\n\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c<\/p>\n
\n$ .\/exo firewall add rke-k8s -p tcp -P 6443 -c 0.0.0.0\/0
\n$ .\/exo firewall add rke-k8s -p tcp -P 10240 -c 0.0.0.0\/0
\n$ .\/exo firewall add rke-k8s ssh<\/p>\n
\n\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c
\n\u2502 TYPE \u2502 SOURCE \u2502 PROTOCOL \u2502 PORT \u2502 DESCRIPTION \u2502 ID \u2502
\n\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c
\n\u2502 INGRESS \u2502 CIDR 0.0.0.0\/0 \u2502 tcp \u2502 22 (ssh) \u2502 \u2502 40d82512-2196-4d94-bc3e-69b259438c57 \u2502
\n\u2502 \u2502 CIDR 0.0.0.0\/0 \u2502 tcp \u2502 10240 \u2502 \u2502 12ceea53-3a0f-44af-8d28-3672307029a5 \u2502
\n\u2502 \u2502 CIDR 0.0.0.0\/0 \u2502 tcp \u2502 6443 \u2502 \u2502 18aa83f3-f996-4032-87ef-6a06220ce850 \u2502
\n\u2502 \u2502 SG \u2502 all \u2502 0 \u2502 \u2502 7de233ad-e900-42fb-8d93-05631bcf2a70 \u2502
\n\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c<\/p>\nOptional: Creating and adding an ssh key<\/h3>\n
\nan ssh key for each instance you bring up. However there are times where you will
\nwant a single administrative ssh key for the cluster. You can have the Exoscale
\nCLI create it or use the CLI to import your own key. To do that, you will use
\nExoscale\u2019s sshkey subcommand.<\/p>\n
\n\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c
\n\u2502 NAME \u2502 FINGERPRINT \u2502
\n\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c
\n\u2502 rke-k8s-key \u2502 0d:03:46:c6:b2:72:43:dd:dd:04:bc:8c:df:84:f4:d1 \u2502
\n\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c
\n—–BEGIN RSA PRIVATE KEY—–
\nMIIC…
\n—–END RSA PRIVATE KEY—–<\/p>\n
\nthat will be your sole means of accessing the cluster using that key name. In
\nboth cases, we will need to make sure that the ssh-agent daemon is running, and
\nour key is added to it. If you haven\u2019t done so already, run:<\/p>\nCreating your Exoscale instances<\/h3>\n
\nsized templates as that will provide enough RAM for both Kubernetes and our
\nsample application to run. The OS Image we will use is Ubuntu-16.04 due to the
\nversion of Docker required by RKE to bring up our cluster. Lastly, we use 10g of
\ndisk space which will be enough to experiment with.<\/p>\n
\nhave enough RAM to bootstrap the Kubernetes cluster.<\/p><\/blockquote>\n
\nThis is as easy as creating a YAML file to describe our actions, and specifying
\nthe file on the Exoscale command line:<\/p>\n
\npackage_upgrade: true<\/p>\n
\n– curl<\/p>\n
\n– “curl https:\/\/releases.rancher.com\/install-docker\/17.03.sh| bash”
\n– “usermod -aG docker ubuntu”
\n– “mkdir \/data”<\/p>\n
\nmode: reboot<\/p>\n
\n.\/exo vm create rancher-$i
\n–cloud-init-file cloud-init.yml
\n–service-offering medium
\n–template “Ubuntu 16.04 LTS”
\n–security-group rke-k8s
\n–disk 10
\n> done
\nCreating private SSH key
\nDeploying “rancher-1” …………. success!<\/p>\n
\nssh -i “\/home\/cab\/.exoscale\/instances\/85fc654f-5761-4a02-b501-664ae53c671d\/id_rsa” [email protected]<\/a><\/p>\n
\nHost rancher-1
\nHostName 185.19.29.207
\nUser ubuntu
\nIdentityFile \/home\/cab\/.exoscale\/instances\/85fc654f-5761-4a02-b501-664ae53c671d\/id_rsa<\/p>\n
\nYou’re the sole owner of the private key.
\nBe cautious with it.<\/p>\n
\n–keypair <common key> argument where common key is the key name you chose
\nto upload.<\/p>\n
\ninstances configured with docker and ready to go. A sample configuration will
\nresemble the following when you run .\/exo vm list:<\/p>\n
\n\u2502 NAME \u2502 SECURITY GROUP \u2502 IP ADDRESS \u2502 STATUS \u2502 ZONE \u2502 ID \u2502
\n\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c
\n\u2502 rancher-4 \u2502 rke-k8s \u2502 159.100.240.102 \u2502 Running \u2502 ch-gva-2 \u2502 acb53efb-95d1-48e7-ac26-aaa9b35c305f \u2502
\n\u2502 rancher-3 \u2502 rke-k8s \u2502 159.100.240.9 \u2502 Running \u2502 ch-gva-2 \u2502 6b7707bd-9905-4547-a7d4-3fd3fdd83ac0 \u2502
\n\u2502 rancher-2 \u2502 rke-k8s \u2502 185.19.30.203 \u2502 Running \u2502 ch-gva-2 \u2502 c99168a0-46db-4f75-bd0b-68704d1c7f79 \u2502
\n\u2502 rancher-1 \u2502 rke-k8s \u2502 185.19.30.83 \u2502 Running \u2502 ch-gva-2 \u2502 50605a5d-b5b6-481c-bb34-1f7ee9e1bde8 \u2502
\n\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c<\/p>\nRKE and Kubernetes<\/h2>\n
\nbackup the configuration for a Kubernetes cluster. The core consists of
\na configuration file that has the name of cluster.yml. While RKE
\nsupports the creation of this configuration file with the command rke config,
\nit can be tedious to go through the prompts. Instead, we will pre-create
\nthe config file.<\/p>\n
\nssh_agent_auth: true<\/p>\n
\n– address: [ip address of rancher-1]
\nname: rancher-1
\nuser: ubuntu
\nrole:
\n– controlplane
\n– etcd
\n– worker
\n– address: [ip address of rancher-2]
\nname: rancher-2
\nuser: ubuntu
\nrole:
\n– worker
\n– address: [ip address of rancher-3]
\nname: rancher-3
\nuser: ubuntu
\nrole:
\n– worker
\n– address: [ip address of rancher-4]
\nname: rancher-4
\nuser: ubuntu
\nrole:
\n– worker<\/p>\n\n
\nshould be changed to reflect your private key location. Otherwise, you will
\nneed to move the ssh_key_path line to be inside each node entry and change
\nthe path to match the key generated for each instance that was created.<\/li>\n
\nprevious step.<\/li>\n
\nbring up the Kubernetes cluster. There will be a flurry of status updates as the
\ndocker containers for the various Kubernetes components are downloaded into each
\nnode, installed, and configured.<\/p>\nConfiguring and using kubectl<\/h3>\n
\nkube_config_cluster.yml which is used by kubectl to communicate with the cluster.
\nTo make running kubctl easier going forward, you will want to set the environment
\nvariable KUBECONFIG so you don\u2019t need to pass the config parameter each time:<\/p>\n
\nyou a listing of all registered nodes, their roles as defined from the
\ncluster.yml file above, and the Kubernetes version each node is running running.<\/p>\n
\nNAME STATUS ROLES AGE VERSION
\n159.100.240.102 Ready worker 3m v1.11.1
\n159.100.240.9 Ready worker 3m v1.11.1
\n185.19.30.203 Ready worker 3m v1.11.1
\n185.19.30.83 Ready controlplane,etcd,worker 3m v1.11.1<\/p>\n
\nNAME STATUS MESSAGE ERROR
\nscheduler Healthy ok
\ncontroller-manager Healthy ok
\netcd-0 Healthy {“health”: “true”}<\/p>\n
\nRancher\u2019s documentation page.<\/a><\/p><\/blockquote>\nOptional: Installing the Kubernetes Dashboard<\/h3>\n
\nwill install the Kubernetes dashboard. To install the dashboard, you will run:<\/p>\n
\nit is from inside the Kubernetes cluster. To expose the dashboard port onto your
\nworkstation so that you can interact with it, you will need to proxy the port by
\nrunning:<\/p>\n
\nhttp:\/\/localhost:8001<\/a>.<\/p>\n
\nauthenticate your session. This will require a token from a specific
\nsubsystem utilizing a set of secrets that were generated at the time we ran
\nrke up. The following command will extract the correct token that you can use
\nto authenticate against for the dashboard:<\/p>\n
\n`.\/kubectl -n kube-system get secrets |awk ‘\/clusterrole-aggregation-controller\/ ‘`
\n|awk ‘\/token:\/ ‘<\/p>\n
\non the dashboard webpage, and explore the details of your cluster.<\/p>\n![\"Kubernetes](\"https:\/\/i.imgur.com\/aZZ9iow.png\")
<\/p>\nAdding Cassandra to Kubernetes<\/h2>\n
\nThis will be a simple cluster that will use the local disks for storage. This
\nwill give us something to play with when it comes to installing a service, and
\nseeing what happens inside Kubernetes.<\/p>\n
\nexposed by Kubernetes, and an application definition file that specifies things
\nlike networking, storage configuration, number of replicas, etc.<\/p>\nStep 1: Cassandra Service File<\/h3>\n
\nkind: Service
\nmetadata:
\nlabels:
\napp: cassandra
\nname: cassandra
\nspec:
\nclusterIP: None
\nports:
\n– port: 9042
\nselector:
\napp: cassandra<\/p>\n
\nNAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
\ncassandra ClusterIP None <none> 9042\/TCP 46s<\/p>\n
\nKubernetes Service Networking Guide<\/a>.<\/p><\/blockquote>\nCassandra StatefulSet<\/h3>\n
\nis a type of Kubernetes workload where the application is expected to persist
\nsome kind of state such as our Cassandra example.<\/p>\n
\nand apply it:<\/p>\n
\nstatefulset.apps\/cassandra created
\nstorageclass.storage.k8s.io\/fast created<\/p>\n
\nNAME DESIRED CURRENT AGE
\ncassandra 3 3 4m<\/p>\n
\nCassandra is up:<\/p>\n
\nDatacenter: DC1-K8Demo
\n======================
\nStatus=Up\/Down
\n|\/ State=Normal\/Leaving\/Joining\/Moving
\n— Address Load Tokens Owns (effective) Host ID Rack
\nUN 10.42.2.2 104.55 KiB 32 59.1% ac30ba66-bd59-4c8d-ab7b-525daeb85904 Rack1-K8Demo
\nUN 10.42.1.3 84.81 KiB 32 75.0% 92469b85-eeae-434f-a27d-aa003531cff7 Rack1-K8Demo
\nUN 10.42.3.3 70.88 KiB 32 65.9% 218a69d8-52f2-4086-892d-f2c3c56b05ae Rack1-K8Demo<\/p>\n
\nwill run:<\/p>\n
\nchange the value 3 to 4, save and exit. You should see the following with your
\nnext invocation of kubectl:<\/p>\n
\nNAME DESIRED CURRENT AGE
\ncassandra 4 4 10m<\/p>\n
\nDatacenter: DC1-K8Demo
\n======================
\nStatus=Up\/Down
\n|\/ State=Normal\/Leaving\/Joining\/Moving
\n— Address Load Tokens Owns (effective) Host ID Rack
\nUN 10.42.2.2 104.55 KiB 32 51.0% ac30ba66-bd59-4c8d-ab7b-525daeb85904 Rack1-K8Demo
\nUN 10.42.1.3 84.81 KiB 32 56.7% 92469b85-eeae-434f-a27d-aa003531cff7 Rack1-K8Demo
\nUN 10.42.3.3 70.88 KiB 32 47.2% 218a69d8-52f2-4086-892d-f2c3c56b05ae Rack1-K8Demo
\nUN 10.42.0.6 65.86 KiB 32 45.2% 275a5bca-94f4-439d-900f-4d614ba331ee Rack1-K8Demo<\/p>\n![\"Looking](\"https:\/\/i.imgur.com\/uWHbSbu.png\")
<\/p>\nFinal Note<\/h2>\n
\nKubernetes makes it easy to scale your cluster up to account for load, however to
\nensure data gets preserved, Kubernetes will keep all data in place when you scale
\nthe number of nodes down. What this means is that you will be responsible for
\nensuring proper backups are made and everything is deleted before you can
\nconsider the application cleaned up.<\/p>\n![\"Chris](\"https:\/\/rancher.com\/img\/bio\/chris-baumbauer.jpg\")
<\/p>\n![\"github\"](\"https:\/\/rancher.com\/img\/icon-github.svg\"){kind=icon}
<\/a><\/p>\n