container.training/slides/k8s/k9s.md

k9s

• Somewhere in between CLI and GUI (or web UI), we can find the magic land of TUI

  • Text-based user interfaces

  • often using libraries like curses and its successors

• Some folks love them, some folks hate them, some are indifferent ...

• But it's nice to have different options!

• Let's see one particular TUI for Kubernetes: k9s

---

Installing k9s

• If you are using a training cluster or the shpod image, k9s is pre-installed

• Otherwise, it can be installed easily:

  • with various package managers

  • or by fetching a binary release

• We don't need to set up or configure anything

  (it will use the same configuration as kubectl and other well-behaved clients)

• Just run k9s to fire it up!

---

What kind to we want to see?

• Press : to change the type of resource to view

• Then type, for instance, ns or namespace or nam[TAB], then [ENTER]

• Use the arrows to move down to e.g. kube-system, and press [ENTER]

• Or, type /kub or /sys to filter the output, and press [ENTER] twice

  (once to exit the filter, once to enter the namespace)

• We now see the pods in kube-system!

---

Interacting with pods

• l to view logs

• d to describe

• s to get a shell (won't work if sh isn't available in the container image)

• e to edit

• shift-f to define port forwarding

• ctrl-k to kill

• [ESC] to get out or get back

---

Quick navigation between namespaces

• On top of the screen, we should see shortcuts like this:

  <0> all
  <1> kube-system
  <2> default
  

• Pressing the corresponding number switches to that namespace

  (or shows resources across all namespaces with 0)

• Locate a namespace with a copy of DockerCoins, and go there!

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Interacting with Deployments

• View Deployments (type : deploy [ENTER])

• Select e.g. worker

• Scale it with s

• View its aggregated logs with l

---

Exit

• Exit at any time with Ctrl-C

• k9s will "remember" where you were

  (and go back there next time you run it)

---

Pros

• Very convenient to navigate through resources

  (hopping from a deployment, to its pod, to another namespace, etc.)

• Very convenient to quickly view logs of e.g. init containers

• Very convenient to get a (quasi) realtime view of resources

  (if we use watch kubectl get a lot, we will probably like k9s)

---

Cons

• Doesn't promote automation / scripting

  (if you repeat the same things over and over, there is a scripting opportunity)

• Not all features are available

  (e.g. executing arbitrary commands in containers)

---

Conclusion

Try it out, and see if it makes you more productive!

???

:EN:- The k9s TUI :FR:- L'interface texte k9s