container.training/slides/k8s/yamldeploy.md

Deploying with YAML

• So far, we created resources with the following commands:

  • kubectl run

  • kubectl create deployment

  • kubectl expose

• We can also create resources directly with YAML manifests

---

kubectl apply vs create

• kubectl create -f whatever.yaml

  • creates resources if they don't exist

  • if resources already exist, don't alter them
    (and display error message)

• kubectl apply -f whatever.yaml

  • creates resources if they don't exist

  • if resources already exist, update them
    (to match the definition provided by the YAML file)

  • stores the manifest as an annotation in the resource

---

Creating multiple resources

• The manifest can contain multiple resources separated by ---

 kind: ...
 apiVersion: ...
 metadata: ...
   name: ...
 ...
 ---
 kind: ...
 apiVersion: ...
 metadata: ...
   name: ...
 ...

---

Creating multiple resources

• The manifest can also contain a list of resources

 apiVersion: v1
 kind: List
 items:
 - kind: ...
   apiVersion: ...
   ...
 - kind: ...
   apiVersion: ...
   ...

---

Deploying dockercoins with YAML

• We provide a YAML manifest with all the resources for Dockercoins

  (Deployments and Services)

• We can use it if we need to deploy or redeploy Dockercoins

.exercise[

• Deploy or redeploy Dockercoins:

  kubectl apply -f ~/container.training/k8s/dockercoins.yaml
  

]

(If we deployed Dockercoins earlier, we will see warning messages, because the resources that we created lack the necessary annotation. We can safely ignore them.)