Edited, memorised or added to reading list

on 19-Jun-2019 (Wed)

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Flashcard 4146720804108

Question
In kubernetes, [...] can be thought of as a logical server that contain one or more (but mostly one) running applications, running as a container.
Answer
pods


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Flashcard 4146722901260

Question
In kubernetes, [...] are actual (physical or cloud) servers that run one or more pods.
Answer
nodes


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Flashcard 4146725522700

Question
In kubernetes, [...] are wrappers around a container and can be though of as a logical server, while nodes are the actual phyisical or cloud servers that run them.
Answer
pods


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The Internet has led to the creation of a digital society

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pdf

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Flashcard 4147087281420

Question
The Internet has [...] the creation of a digital society
Answer
led to


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Parent (intermediate) annotation

Open it
The Internet has led to the creation of a digital society

Original toplevel document (pdf)

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Flashcard 4147102223628

Question
In kubernetes, if you want to create a deployment of pods, the best/easiest/fastest command to use is: "kubectl [...] " command
Answer

run

^^^ e.g.: kubectl run kubernetes-bootcamp --image=gcr.io/google-samples/kubernetes-bootcamp:v1 --port=8080 --replicas=3


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Flashcard 4147104320780

Question
In kubernetes, a set of pods all running the same container app, is called a [...] of pods.
Answer
replica


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Flashcard 4147106417932

Question
In kubernetes, if you have a replica (i.e. set) of pods (each with a container running the same app), you can group them together for the purpose of internal, or more importantly, external exposure via a kubernetes concept called [...]
Answer

service

^^ note that service is created behind the scenes via issueing the "kubectl expose" command.


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Flashcard 4147108515084

Question
In kubernetes, a [...] is a way to logically group a replica (i.e. set) of pods together for the purpose of allowing them to be accessed internally (within the cluster) and more importantly externally (from outside the cluster).
Answer
service


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Flashcard 4147110612236

Question

In kubernetes, issue cammand to run a three pod deployment of the following docker image: "gcr.io/google-samples/kubernetes-bootcamp:v1". You can use port "8080" and name the deployment "kubernetes-bootcamp"

Answer

kubectl run kubernetes-bootcamp --image=gcr.io/google-samples/kubernetes-bootcamp:v1 --port=8080 --replicas=3


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Flashcard 4147112709388

Question
In kubernetes, while the "kubectl run" command will create a deployment based on a docker image provided (e.g. : kubectl run kubernetes-bootcamp --image=gcr.io/google-samples/kubernetes-bootcamp:v1 --port=8080 --replicas=3), the kubectl [...] command will create a service from these 3 pods so they can be accessed from outside the cluster
Answer
expose


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Flashcard 4147114806540

Question

In kubernetes, let say you do a 3 pod deployment called "kubernetes-bootcamp" using docker image "gcr.io/google-samples/kubernetes-bootcamp:v1" as follows:

kubectl run kubernetes-bootcamp --image=gcr.io/google-samples/kubernetes-bootcamp:v1 --port=8080 --replicas=3

Run command to get these pods to be accessible from a dynamic port on the host machine:

Answer

kubectl expose deployment kubernetes-bootcamp --type=NodePort --port=8080

^^ the key point here is knowing the "kubectl expose" command and how to use it

^^^ note above command creates a service (also called "kubernetes-bootcamp"), which allows the pods to be exposed via a dynamic port, e.g. via: "curl $(hostname):30993", where 30993 is the dynamic port generated.

^^^^ note the --type param is set to NodePort, which will expose the nodes via a dynamiclly generated port, so you can access from the node/host you are running kubectl from. There are other more advanced/better --type options, refer to the k8s docs


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Flashcard 4147116903692

Question
In kubernets, [...] s are used to add metadata key/value pairs to resrouces (such as pods), which can then be used for easier searching/grouping of these resources.
Answer
labels


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Flashcard 4147119000844

Question
In kubernetes, say you have a pod called "kevintest-5sdflkj-923s" (just FYI: "kevintest" is the associated deployment name), issue command to add a app=v1 metadata tag to this pod:
Answer

kubectl label pod kevintest-5sdflkj-923s app=v1

^^ note the format follows the "kubectl action resrouce" formula, where "label" is action, "pod" is resource, then comes the pod name and the label key/value to add

^^^ note that ofcourse labelling can also be done in the deployment .yaml file, if you use this approach for deployment.


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Flashcard 4147121884428

Question

In kubernetes, issue command to get simple list of all pods that have the following label (i.e.metadata tag):
app=v1

Answer
kubectl get pods -l app=v1


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Flashcard 4147125030156

Question
In kubernetes, scaling (up or down) an app is accomplished by changing the number of [...] s in a Deployment. Hint: answer is not "pod", as that is too obvious.
Answer
replicas


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Flashcard 4147127127308

Question
In kubernetes, when you use the "kubectl scale" command to scale up/down your pods, this is reflected back when you use the "kubectl get [...] (s)" command
Answer
deployment(s)


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Flashcard 4147129224460

Question
In kubernetes, when you scale up your deployment to use multiple pods, load-balancing is automatically handled by the kubernetes [...] used to expose the deployment (to external traffic).
Answer
service


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Flashcard 4147131321612

Question

In kuberentes, let say you setup a one pod deployment with the following command:

kubectl run kubernetes-bootcamp --image=gcr.io/google-samples/kubernetes-bootcamp:v1 --port=8080

Issue command to scale up the deployment to 4 pods

Answer
kubectl scale deployment kubernetes-bootcamp --replicas=4

^^ after running above command, when you then run "kubectl get deployment kubernetes-bootcamp", it will show that 4 pods are in READY state in the deployment now


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Flashcard 4147133943052

Question
In kubernets, explain in detail what happens, by default, when you do a rolling update via the "kubectl set image" command?
Answer
One old pod is taken down and a whole new pod is created in its place with the update image, this continues until all old pods are replaced with new pods with the new image. By default 1 pod is taken down at a time at most, and 1 new one created at most at a time, but this is configurable.


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Flashcard 4147136040204

Question
In kubernetes, you can initiate a rolling update (where, by default, one pod is taken down and new one created with new conatiner image), by using the "kubectl [...] [...] " command
Answer

set image

^^ e.g.

kubectl set image deployment.v1.apps/kubernetes-bootcamp kubernetes-bootcamp=gcr.io/google-sample/kubernetes-bootcamp:v2

, where kubernetes-bootcamp= referes to container image name which you can get from "kubectl describe deploymen kubernetes-bootcamp"


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Flashcard 4147138137356

Question
In kubernetes, if you do a rolling update (via "kubectl set image" command) and things go bad (i.e. one or more pods are no longer available), you can rollback via the "kubectl [...] [...] " command
Answer

kubectl rollout undo

^^ you can either rollback to immediate previous version, e.g.: kubectl rollout undo deployment kubernetes-bootcamp

^^^ or you can rollback to a specific previous version number, e.g.: kubectl rollout undo deployment kubernetes-bootcamp --to-revision=2

^^^^ to get the previuos versions/revision of a deployment, you can do "kubectl rollout history deployment kubernetes-bootcamp"


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Flashcard 4147140496652

Question

- In kubernetes, if you do several rolling updates (via "kubectl set image" commands), you can check the deployment version history via the "kubectl [...] [...] " command.

Answer

kubectl rollout history

^^ e.g.: kubectl rollout history deployment kubernetes-bootcamp


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Flashcard 4147142593804

Question

In kubernetes, let's say you have 4 pods, in deployment "kubernetes-bootcamp", that are running container image "gcr.io/google-sample/kubernetes-bootcamp:v1", issue command to do rolling upgrade to image "gcr.io/google-sample/kubernetes-bootcamp:v2", fillout below occultions:

kubectl [...] [...] deployment.v1.apps/kubernetes-bootcamp kubernetes-bootcamp= [...]

NOTE: the kubernetes-bootcamp= part is referring to the conatiner name (which you can get from "kubectl describe deployment kubernetes-bootcamp"

Answer

kubectl set image deployment.v1.apps/kubernetes-bootcamp kubernetes-bootcamp=gcr.io/google-sample/kubernetes-bootcamp:v2


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Flashcard 4147144690956

Question

In kubernetes, if you do a rolling update to upgrade container images of your pods via following command (note deployment is called "kubernetes-bootcamp"):

kubectl set image deployment.v1.apps/kubernetes-bootcamp kubernetes-bootcamp=gcr.io/google-sample/kubernetes-bootcamp:v2

Assume update went bad (i.e. one or more pods are down post-update), issue command to roll back to imediate previous version

Answer
kubectl rollout undo deployment kubernetes-bootcamp


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