updates

dockerfiles/tomcat-eg/Dockerfile1

@@ -0,0 +1,6 @@
+FROM tomcat
+RUN apt-get update && apt-get -y upgrade
+WORKDIR /usr/local/tomcat
+COPY tomcat-users.xml /usr/local/tomcat/conf/tomcat-users.xml
+COPY context.xml /usr/local/tomcat/webapps/manager/META-INF/context.xml
+EXPOSE 8080

dockerfiles/tomcat-eg/Dockerfile2

@@ -0,0 +1,5 @@
+FROM tomcat
+RUN apt-get update && apt-get -y upgrade
+WORKDIR /usr/local/tomcat
+COPY ../target/HelloWorld-0.0.1-SNAPSHOT.war /usr/local/tomcat/webapps/
+EXPOSE 8080

dockerfiles/tomcat-eg/context.xml

@@ -0,0 +1,5 @@
+<Context antiResourceLocking="false" privileged="true" >
+    <!-- <Valve className="org.apache.catalina.valves.RemoteAddrValve"
+        allow="127\.\d+\.\d+\.\d+|::1|0:0:0:0:0:0:0:1" /> -->
+    <Manager sessionAttributeValueClassNameFilter="java\.lang\.(?:Boolean|Integer|Long|Number|String)|org\.apache\.catalina\.filters\.CsrfPreventionFilter\$LruCache(?:\$1)?|java\.util\.(?:Linked)?HashMap"/>
+</Context>

dockerfiles/tomcat-eg/tomcat-users.xml

@@ -0,0 +1,6 @@
+<tomcat-users xmlns="http://tomcat.apache.org/xml"
+              xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+              xsi:schemaLocation="http://tomcat.apache.org/xml tomcat-users.xsd"
+              version="1.0">
+  <user username="admin" password="secret" roles="manager-gui"/>
+</tomcat-users>

kmaster/KubernetesUbuntuInstallation.txt

@@ -1,5 +1,8 @@
 Get amazon linux 20.04
 
+
+sudo su
+
 hostnamectl set-hostname kmaster
 hostnamectl set-hostname kworker
 
@@ -71,9 +74,22 @@ systemctl enable kubelet
 
 
    kubeadm init
+
+mkdir -p $HOME/.kube
+sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
+sudo chown $(id -u):$(id -g) $HOME/.kube/config   
+exit
+mkdir -p $HOME/.kube
+sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
+sudo chown $(id -u):$(id -g) $HOME/.kube/config   
+
+copy the join command and execute it on the worker node.
+	should be done in 24 hours.
+
 
 
    watch -n 1 kubectl get nodes
+		Status: NotReady
    watch -n 1 kubectl get po -n kube-system
    kubectl apply -f https://github.com/weaveworks/weave/releases/download/v2.8.1/weave-daemonset-k8s.yaml
    watch -n 1 kubectl get po -n kube-system

yaml/etcdbackup/Notes.txt

@@ -8,6 +8,7 @@ Instead copy it from the running container.
 
 	sample commands used during backup/restore/update of nodes
 		apt install etcd-client #This can get you trouble. if the version is not latest it will fail
+			etcdctl --version
 
 		docker ps - get etcd container
 		sudo docker cp etcd:/usr/local/bin/etcdctl /usr/local/bin

yaml/troubleshooting/Notes.txt

@@ -50,17 +50,79 @@ Control plane failures
 [email protected]
 
 Application debugging
-	1. Application environment name can 
+	1. Application environment variable's name can 
 		mis match with database service name.
 		mis match with dtabase port
+	2. service lable can mismatch with pod's labels
+		service port can mismatch with target port 
+
+	3. Front end port number mismatch with NodePort 
+	4. Confirm the environment variable defn. 
+		e.g. db pwd is wrong than what is mentioned in quesstion
 
+	Important point: 
+		k describe svc <name>
+			is the endpoint reported.
+
+Troubleshooting Control Plane 
+-----------------------------
+Some of the pods can be failing 
+	Is the Node ready?
+	Describe the pod/deployment/replicaset
+
+	Everything good - but still nothing is happening 
+	Check control plane.
+	kubectl get pod -n kube-system
+	If any of the below is not working 
+		scheduler
+		controller
+		etcd
+		api-server 
+			for this you would get a diff. error.
+
+	Check static pods 
+		/etc/kubernetes/manifests/
+
+	ports where services listen 
+		api-server: 6443
+		etcd: 
+			2379: client communication 
+			2380: peer communication 
+		controller: 10250 
+		scheduler: 10251
+
+Troubleshoot worker node failures
+----------------------------------
+
+	Worker node not ready.
+	kubectl describe node <name>
+	kubectl get pod -n kube-system 
+		check 
+			proxy 
+			network plugin 
+	systemctl status kubelet 
+	systemctl restart kubelet 
+	journalctl -u kubelet
+	kubelet config files 
+		/etc/kubernetes/kubelet.config
+		/var/lib/kubelet/config.yml 
 
 
 Network Troubleshooting
 Network Plugin in kubernetes
 --------------------
+
+
 
-Kubernetes uses CNI plugins to setup network. The kubelet is responsible for executing plugins as we mention the following parameters in kubelet configuration.
+References: 
+	Debug Service issues:
+        https://kubernetes.io/docs/tasks/debug-application-cluster/debug-service/
+
+DNS Troubleshooting:
+		https://kubernetes.io/docs/tasks/administer-cluster/dns-debugging-resolution/
+
+Kubernetes uses CNI plugins to setup network. 
+The kubelet is responsible for executing plugins as we mention the following parameters in kubelet configuration.
 
 - cni-bin-dir:   Kubelet probes this directory for plugins on startup
 
@@ -145,15 +207,10 @@ In large scale Kubernetes clusters, CoreDNS's memory usage is predominantly affe
 Kubernetes resources for coreDNS are:   
 
 a service account named coredns,
-
 cluster-roles named coredns and kube-dns
-
 clusterrolebindings named coredns and kube-dns, 
-
 a deployment named coredns,
-
 a configmap named coredns and a
-
 service named kube-dns.
 
 

yaml/volumes/nfs/NFSWithKubernetes.txt

@@ -1,5 +1,17 @@
 Install nfs server on ubuntu as mentioned in "NFSSetupNotes.txt"
 
+On kubernetes worker node (if ubuntu)
+-------------------------------------
+apt update -y 
+sudo apt install nfs-common
+
+
+
+Rest all on kubernetes master node
+----------------------------------
+
+
+
 Install kubernetes 
 
 Install helm