Add chapter about cluster upgrades + static pods

slides/k8s/cluster-upgrade.md

@@ -0,0 +1,305 @@
+# Upgrading clusters
+
+- It's *recommended* to run consistent versions across a cluster
+
+  (mostly to have feature parity and latest security updates)
+
+- It's not *mandatory*
+
+  (otherwise, cluster upgrades would be a nightmare!)
+
+- Components can be upgraded one at a time without problems
+
+---
+
+## Checking what we're running
+
+- It's easy to check the version for the API server
+
+.exercise[
+
+- Check the version of kubectl and of the API server:
+  ```bash
+  kubectl version
+  ```
+
+]
+
+- In a HA setup with multiple API servers, they can have different versions
+
+- Running the command above multiple times can return different values
+
+---
+
+## Node versions
+
+- It's also easy to check the version of kubelet
+
+.exercise[
+
+- Check node versions (includes kubelet, kernel, container engine):
+  ```bash
+  kubectl get nodes -o wide
+  ```
+
+]
+
+- Different nodes can run different kubelet versions
+
+- Different nodes can run different kernel versions
+
+- Different nodes can run different container engines
+
+---
+
+## Control plane versions
+
+- If the control plane is self-hosted (running in pods), we can check it
+
+.exercise[
+
+- Show image versions for all pods in `kube-system` namespace:
+  ```bash
+    kubectl --namespace=kube-system get pods -o json \
+            | jq -r '
+              .items[]
+              | [.spec.nodeName, .metadata.name]
+                + 
+                (.spec.containers[].image | split(":"))
+              | @tsv
+              ' \
+            | column -t
+  ```
+
+]
+
+---
+
+## What version are we running anyway?
+
+- When I say, "I'm Kubernetes 1.11", is that the version of:
+
+  - kubectl
+
+  - API server
+
+  - kubelet
+
+  - controller manager
+
+  - something else?
+
+---
+
+## Other versions that are important
+
+- etcd
+
+- kube-dns or CoreDNS
+
+- CNI plugin(s)
+
+- Network controller, network policy controller
+
+- Linux kernel
+
+---
+
+## General guidelines
+
+- To update a component, use whatever was used to install it
+
+- If it's a distro package, update that distro package
+
+- If it's a container or pod, update that container or pod
+
+- If you used configuration management, update with that
+
+---
+
+## Know where your binaries come from
+
+- Sometimes, we need to upgrade *quickly*
+
+  (when a vulnerability is announced and patched)
+
+- If we are using an installer, we should:
+
+  - make sure it's using upstream packages
+
+  - or make sure that whatever packages it uses are current
+
+  - make sure we can tell it to pin specific component versions
+
+---
+
+## In practice
+
+- We are going to update a few cluster components
+
+- We will change the kubelet version on one node
+
+- We will change the version of the API server
+
+- We will work with cluster `test` (nodes `test1`, `test2`, `test3`)
+
+---
+
+## Updating kubelet
+
+- These nodes have been installed using the official Kubernetes packages
+
+- We can therefore use `apt` or `apt-get`
+
+.exercise[
+
+- Log into node `test3`
+
+- View available versions for package `kubelet`:
+  ```bash
+  apt show kubelet -a | grep ^Version
+  ```
+
+- Upgrade kubelet:
+  ```bash
+  apt install kubelet=1.14.1-00
+  ```
+
+]
+
+---
+
+## Checking what we've done
+
+.exercise[
+
+- Log into node `test1`
+
+- Check node versions:
+  ```bash
+  kubectl get nodes -o wide
+  ```
+
+- Create a deployment and scale it to make sure that the node still works
+
+]
+
+---
+
+## Updating the API server
+
+- This cluster has been deployed with kubeadm
+
+- The control plane runs in *static pods*
+
+- These pods are started automatically by kubelet
+
+  (even when kubelet can't contact the API server)
+
+- They are defined in YAML files in `/etc/kubernetes/manifests`
+
+  (this path is set by a kubelet command-line flag)
+
+- kubelet automatically updates the pods when the files are changed
+
+---
+
+## Changing the API server version
+
+- We will edit the YAML file to use a different image version
+
+.exercise[
+
+- Log into node `test1`
+
+- Check API server version:
+  ```bash
+  kubectl version
+  ```
+
+- Edit the API server pod manifest:
+  ```bash
+  sudo vim /etc/kubernetes/manifests/kube-apiserver.yaml
+  ```
+
+- Look for the `image:` line, and update it to e.g. `v1.14.0`
+
+]
+
+---
+
+## Checking what we've done
+
+- The API server will be shortly unavailable while kubelet restarts it
+
+.exercise[
+
+- Check the API server version:
+  ```bash
+  kubectl version
+  ```
+
+]
+
+---
+
+## Updating the whole control plane
+
+- As an example, we'll use kubeadm to upgrade the entire control plane
+
+  (note: this is possible only because the cluster was installed with kubeadm)
+
+.exercise[
+
+- Check what will be upgraded:
+  ```bash
+  sudo kubeadm upgrade plan
+  ```
+
+  (Note: kubeadm is confused by our manual upgrade of the API server.
+  <br/>It thinks the cluster is running 1.14.0!)
+
+<!-- ##VERSION## -->
+
+- Perform the upgrade:
+  ```bash
+  sudo kubeadm upgrade apply v1.14.1
+  ```
+
+]
+
+---
+
+## Updating kubelets
+
+- After updating the control plane, we need to update each kubelet
+
+- This requires to run a special command on each node, to download the config
+
+  (this config is generated by kubeadm)
+
+.exercise[
+
+- Download the configuration on each node, and upgrade kubelet:
+  ```bash
+    for N in 1 2 3; do
+    	ssh node$N sudo kubeadm upgrade node config --kubelet-version v1.14.1
+  	  ssh node $N sudo apt install kubelet=1.14.1-00
+    done
+  ```
+]
+
+---
+
+## Checking what we've done
+
+- All our nodes should now be updated to version 1.14.1
+
+.exercise[
+
+- Check nodes versions:
+  ```bash
+  kubectl get nodes -o wide
+  ```
+
+]

slides/k8s/staticpods.md

@@ -192,6 +192,8 @@ We should see YAML files corresponding to the pods of the control plane.
 
 ---
 
+class: static-pods-exercise
+
 ## Running a static pod
 
 - We are going to add a pod manifest to the directory, and kubelet will run it
@@ -214,6 +216,8 @@ The output should include a pod named `hello-node1`.
 
 ---
 
+class: static-pods-exercise
+
 ## Remarks
 
 In the manifest, the pod was named `hello`.

slides/kube-admin-one.yml

@@ -12,6 +12,7 @@ slides: http://container.training/
 
 exclude:
 - self-paced
+- static-pods-exercise
 
 chapters:
 - shared/title.md
@@ -30,7 +31,7 @@ chapters:
 - - k8s/setup-managed.md
   - k8s/setup-selfhosted.md
   - k8s/cluster-upgrade.md
-  - k8s/cluster-configuration.md
+  - k8s/staticpods.md
   - k8s/cluster-backup.md
   - k8s/cloud-controller-manager.md
   - k8s/bootstrap.md