Tip: Clean evicted pods and dangling docker images

Clean evicted pods

kubectl get pods --all-namespaces -o json | jq '.items[] | select(.status.reason!=null) | select(.status.reason | contains("Evicted")) | "kubectl delete pods \(.metadata.name) -n \(.metadata.namespace)"' | xargs -n 1 bash -c

Clean dangling docker images. 

A dangling image is one that is not tagged and is not referenced by any container.
docker image prune -a -f --filter "until=24h"

Error:no kind is registered in scheme pkg/runtime/scheme.go:101

Symptom:

  When we create controller operator via kubebuilder 2.0  we add deployment type in our controller. But it error out when we "make run"
"no kind is registered for the type v1.Deployment in scheme \"pkg/runtime/scheme.go:101\"

Solution:

   Per kubebuilder 2.0 , "Every set of controllers needs a Scheme, which provides mappings between Kinds and their corresponding Go types."
   We need to add deployment type and all other related to scheme.  Then we can use those objects in our controller.
sample codes :

import (
"flag"
"os"
theapexordsv1 "apexords-operator/api/v1"
"apexords-operator/controllers"
appsv1beta1 "k8s.io/api/apps/v1beta1"
corev1 "k8s.io/api/core/v1"
appsv1 "k8s.io/api/apps/v1"
"k8s.io/apimachinery/pkg/runtime"
_ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
ctrl "sigs.k8s.io/controller-runtime"
"sigs.k8s.io/controller-runtime/pkg/log/zap"

)
var (
scheme   = runtime.NewScheme()
setupLog = ctrl.Log.WithName("setup")
)
func init() {
appsv1beta1.AddToScheme(scheme)
appsv1.AddToScheme(scheme)
corev1.AddToScheme(scheme)
theapexordsv1.AddToScheme(scheme)

}

Error finding current repository: could not determine repository path from module data, package data, or by initializing a module: go

Symptom:

When we run kubebuilder init,  we get below error
$kubebuilder init --domain my.domain
2019/05/29 16:23:45 error finding current repository: could not determine repository path from module data, package data, or by initializing a module: go: cannot determine module path for source directory /home/henryxie/go/kubebuilder-src/my.domain/ (outside GOPATH, no import comments)

Solution:

It is due to go mod init is not working properly.
To fix it
run go mod init  <directory>    ie   go mod init myfirstcontroller
then kubebuilder init --domain my.domain

Tip: How to Git Push Passwordless via SSH for Multiple Internal and External Repositories

Requirement:

   Sometimes we have projects. We need to git commit changes for multiple git repositories. Some repositories are internal, some are external. We would like to setup passwordless for them as well

Solution:

• Setup ssh key for all the git repositories , thus we can git commit passwordless . Refer github doc
• Setup ssh config to use proxy to ssh external git repositories if we are behind proxy in intranet,  ie github.com
• vi .ssh/config , example below

Host=github.com
ProxyCommand=socat - PROXY:your.proxy.ip:%h:%p,proxyport=3128,proxyauth=user:pwd

• git remote -v
• git remote set-url --add --push origin git+ssh://original/repo.git
• git remote set-url --add --push origin git+ssh://another/repo.git

Automation Tool to Create Http Ords and Loadbalancer in K8S

Requirement:

A kubectl plugin that create http and ords( Oracle Rest Data Services) based on Apex (oracle application express) 19.1

Once we have Apex ready . We often need to provision  http and ords for it. We would like to automate http ords and loadbalancer deployment in K8S. Once we have db hostname, port , sys password , apex /ords password. We can deployment a brand new http ords and loadbalancer deployment env via 1 command. We can also delete it via 1 command. ords image is based on docker images of oracle github.

Solution:

Full details and source codes are on github repository