troubleshooting in k8s
concepts
concepts
1. Application Failure
2. Control Plane Failure
3. Worker Node Failure
4. Network failure
fix_app
fix_app
root@controlplane:~# kubectl get all -n alpha
NAME READY STATUS RESTARTS AGE
pod/mysql 1/1 Running 0 2m14s
pod/webapp-mysql-75dfdf859f-g6c69 1/1 Running 0 2m13s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/mysql ClusterIP 10.101.228.242 <none> 3306/TCP 2m14s
service/web-service NodePort 10.105.190.144 <none> 8080:30081/TCP 2m13s
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/webapp-mysql 1/1 1 1 2m13s
NAME DESIRED CURRENT READY AGE
replicaset.apps/webapp-mysql-75dfdf859f 1 1 1 2m13s
root@controlplane:~#
root@controlplane:~# kubectl get svc -n alpha
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
mysql ClusterIP 10.101.228.242 <none> 3306/TCP 5m11s
web-service NodePort 10.105.190.144 <none> 8080:30081/TCP 5m10s
root@controlplane:~# kubectl edit svc mysql -n alpha
A copy of your changes has been stored to "/tmp/kubectl-edit-5wbl3.yaml"
error: At least one of apiVersion, kind and name was changed
root@controlplane:~#
root@controlplane:~# kubectl delete svc mysql -n alpha
service "mysql" deleted
root@controlplane:~# kubectl apply -f /tmp/kubectl-edit-5wbl3.yaml -n alpha
service/mysql-service created
root@controlplane:~# kubectl get svc -n alpha
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
mysql-service ClusterIP 10.101.228.242 <none> 3306/TCP 9s
web-service NodePort 10.105.190.144 <none> 8080:30081/TCP 7m18s
root@controlplane:~#
root@controlplane:~# kubectl get all -n beta
NAME READY STATUS RESTARTS AGE
pod/mysql 1/1 Running 0 2m21s
pod/webapp-mysql-75dfdf859f-cnjvc 1/1 Running 0 2m21s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/mysql-service ClusterIP 10.105.137.114 <none> 3306/TCP 2m21s
service/web-service NodePort 10.98.182.217 <none> 8080:30081/TCP 2m20s
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/webapp-mysql 1/1 1 1 2m21s
NAME DESIRED CURRENT READY AGE
replicaset.apps/webapp-mysql-75dfdf859f 1 1 1 2m22s
root@controlplane:~#
root@controlplane:~# kubectl get all -n delta
NAME READY STATUS RESTARTS AGE
pod/mysql 1/1 Running 0 32s
pod/webapp-mysql-67cfc57cbc-s2t4r 1/1 Running 0 32s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/mysql-service ClusterIP 10.105.81.242 <none> 3306/TCP 32s
service/web-service NodePort 10.103.208.202 <none> 8080:30081/TCP 32s
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/webapp-mysql 1/1 1 1 32s
NAME DESIRED CURRENT READY AGE
replicaset.apps/webapp-mysql-67cfc57cbc 1 1 1 32s
root@controlplane:~#
root@controlplane:~# kubectl get all -n epsilon
NAME READY STATUS RESTARTS AGE
pod/mysql 1/1 Running 0 3m32s
pod/webapp-mysql-75dfdf859f-8zfkr 1/1 Running 0 2m14s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/mysql-service ClusterIP 10.101.73.160 <none> 3306/TCP 3m33s
service/web-service NodePort 10.111.193.14 <none> 8080:30081/TCP 3m32s
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/webapp-mysql 1/1 1 1 3m32s
NAME DESIRED CURRENT READY AGE
replicaset.apps/webapp-mysql-67cfc57cbc 0 0 0 3m32s
replicaset.apps/webapp-mysql-75dfdf859f 1 1 1 2m14s
root@controlplane:~# kubectl edit pod/webapp-mysql-75dfdf859f-8zfkr -n epsilon
Edit cancelled, no changes made.
root@controlplane:~# kubectl edit pod/mysql -n epsilon
error: pods "mysql" is invalid
A copy of your changes has been stored to "/tmp/kubectl-edit-8brmz.yaml"
error: Edit cancelled, no valid changes were saved.
root@controlplane:~# kubectl delete pod mysql -n epsilon
pod "mysql" deleted
kubectl apply -f /tmp/kubectl-edit-8brmz.yaml -n epsilon
root@controlplane:~# kubectl get all -n zeta
NAME READY STATUS RESTARTS AGE
pod/mysql 1/1 Running 0 26s
pod/webapp-mysql-67cfc57cbc-mbcsj 1/1 Running 0 26s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/mysql-service ClusterIP 10.103.164.30 <none> 3306/TCP 27s
service/web-service NodePort 10.102.1.35 <none> 8080:30088/TCP 26s
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/webapp-mysql 1/1 1 1 26s
NAME DESIRED CURRENT READY AGE
replicaset.apps/webapp-mysql-67cfc57cbc 1 1 1 26s
root@controlplane:~# kubectl edit service/web-service -n zeta
Edit cancelled, no changes made.
root@controlplane:~# kubectl edit service/mysql-service -n zeta
Edit cancelled, no changes made.
root@controlplane:~# kubectl edit pod/mysql -n zeta
A copy of your changes has been stored to "/tmp/kubectl-edit-b9kox.yaml"
error: Edit cancelled, no valid changes were saved.
root@controlplane:~# kubectl delete pod mysql -n zeta
pod "mysql" deleted
root@controlplane:~#
root@controlplane:~# kubectl apply -f /tmp/kubectl-edit-b9kox.yaml -n zeta
pod/mysql created
root@controlplane:~#
fix_controlplane
fix_controlplane
root@controlplane:~# kubectl get cs
Warning: v1 ComponentStatus is deprecated in v1.19+
NAME STATUS MESSAGE ERROR
controller-manager Unhealthy Get "http://127.0.0.1:10252/healthz": dial tcp 127.0.0.1:10252: connect: connection refused
scheduler Unhealthy Get "http://127.0.0.1:10251/healthz": dial tcp 127.0.0.1:10251: connect: connection refused
etcd-0 Healthy {"health":"true"}
root@controlplane:~# kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-74ff55c5b-dmn7d 1/1 Running 0 11m
coredns-74ff55c5b-kcj74 1/1 Running 0 11m
etcd-controlplane 1/1 Running 0 11m
kube-apiserver-controlplane 1/1 Running 0 11m
kube-controller-manager-controlplane 1/1 Running 0 11m
kube-flannel-ds-nvjfr 1/1 Running 0 11m
kube-proxy-wsgdk 1/1 Running 0 11m
kube-scheduler-controlplane 0/1 CrashLoopBackOff 3 89s
root@controlplane:~#
root@controlplane:~# kubectl get cs
Warning: v1 ComponentStatus is deprecated in v1.19+
NAME STATUS MESSAGE ERROR
controller-manager Unhealthy Get "http://127.0.0.1:10252/healthz": dial tcp 127.0.0.1:10252: connect: connection refused
scheduler Unhealthy Get "http://127.0.0.1:10251/healthz": dial tcp 127.0.0.1:10251: connect: connection refused
etcd-0 Healthy {"health":"true"}
root@controlplane:~# kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-74ff55c5b-dmn7d 1/1 Running 0 11m
coredns-74ff55c5b-kcj74 1/1 Running 0 11m
etcd-controlplane 1/1 Running 0 11m
kube-apiserver-controlplane 1/1 Running 0 11m
kube-controller-manager-controlplane 1/1 Running 0 11m
kube-flannel-ds-nvjfr 1/1 Running 0 11m
kube-proxy-wsgdk 1/1 Running 0 11m
kube-scheduler-controlplane 0/1 CrashLoopBackOff 3 89s
root@controlplane:~#
root@controlplane:/etc/kubernetes/manifests# kubectl get all
NAME READY STATUS RESTARTS AGE
pod/app-586bddbc54-djlqq 1/1 Running 0 38s
pod/app-586bddbc54-gkknn 1/1 Running 0 12m
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 23m
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/app 2/2 2 2 12m
NAME DESIRED CURRENT READY AGE
replicaset.apps/app-586bddbc54 2 2 2 12m
root@controlplane:/etc/kubernetes/manifests#
fix_nodefailure
fix_nodefailure
root@controlplane:~# kubectl get nodes -o wide
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
controlplane Ready control-plane,master 20m v1.20.0 10.53.130.3 <none> Ubuntu 18.04.5 LTS 5.4.0-1052-gcp docker://19.3.0
node01 Ready <none> 19m v1.20.0 10.53.130.6 <none> Ubuntu 18.04.5 LTS 5.4.0-1052-gcp docker://19.3.0
root@controlplane:~#
root@controlplane:~# kubectl get nodes
NAME STATUS ROLES AGE VERSION
controlplane Ready control-plane,master 21m v1.20.0
node01 NotReady <none> 20m v1.20.0
root@controlplane:~#
root@node01:~# cd /etc/systemd/system/kubelet.service.d/
root@node01:/etc/systemd/system/kubelet.service.d# pwd
/etc/systemd/system/kubelet.service.d
root@node01:/etc/systemd/system/kubelet.service.d# cat 10-kubeadm.conf
# Note: This dropin only works with kubeadm and kubelet v1.11+
[Service]
Environment="KUBELET_KUBECONFIG_ARGS=--bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --kubeconfig=/etc/kubernetes/kubelet.conf"
Environment="KUBELET_CONFIG_ARGS=--config=/var/lib/kubelet/config.yaml"
# This is a file that "kubeadm init" and "kubeadm join" generates at runtime, populating the KUBELET_KUBEADM_ARGS variable dynamically
EnvironmentFile=-/var/lib/kubelet/kubeadm-flags.env
# This is a file that the user can use for overrides of the kubelet args as a last resort. Preferably, the user should use
# the .NodeRegistration.KubeletExtraArgs object in the configuration files instead. KUBELET_EXTRA_ARGS should be sourced from this file.
EnvironmentFile=-/etc/default/kubelet
ExecStart=
ExecStart=/usr/bin/kubelet $KUBELET_KUBECONFIG_ARGS $KUBELET_CONFIG_ARGS $KUBELET_KUBEADM_ARGS $KUBELET_EXTRA_ARGS
root@node01:/etc/systemd/system/kubelet.service.d#
root@controlplane:~# kubectl get nodes
NAME STATUS ROLES AGE VERSION
controlplane Ready control-plane,master 27m v1.20.0
node01 Ready <none> 27m v1.20.0
root@controlplane:~#
root@node01:/var/lib/kubelet# service kubelet status
● kubelet.service - kubelet: The Kubernetes Node Agent
Loaded: loaded (/lib/systemd/system/kubelet.service; enabled; vendor preset: enabled)
Drop-In: /etc/systemd/system/kubelet.service.d
└─10-kubeadm.conf
Active: active (running) since Wed 2021-09-29 00:18:25 UTC; 17s ago
Docs: https://kubernetes.io/docs/home/
Main PID: 12506 (kubelet)
Tasks: 35 (limit: 5529)
CGroup: /system.slice/kubelet.service
└─12506 /usr/bin/kubelet --bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --k
Sep 29 00:18:27 node01 kubelet[12506]: I0929 00:18:27.690184 12506 topology_manager.go:187] [topolo
Sep 29 00:18:27 node01 kubelet[12506]: I0929 00:18:27.789994 12506 reconciler.go:224] operationExec
Sep 29 00:18:27 node01 kubelet[12506]: I0929 00:18:27.790057 12506 reconciler.go:224] operationExec
Sep 29 00:18:27 node01 kubelet[12506]: I0929 00:18:27.790076 12506 reconciler.go:224] operationExec
Sep 29 00:18:27 node01 kubelet[12506]: I0929 00:18:27.790100 12506 reconciler.go:224] operationExec
Sep 29 00:18:27 node01 kubelet[12506]: I0929 00:18:27.790117 12506 reconciler.go:224] operationExec
Sep 29 00:18:27 node01 kubelet[12506]: I0929 00:18:27.790133 12506 reconciler.go:224] operationExec
Sep 29 00:18:27 node01 kubelet[12506]: I0929 00:18:27.790206 12506 reconciler.go:224] operationExec
Sep 29 00:18:27 node01 kubelet[12506]: I0929 00:18:27.790322 12506 reconciler.go:224] operationExec
Sep 29 00:18:27 node01 kubelet[12506]: I0929 00:18:27.790363 12506 reconciler.go:157] Reconciler: s
root@node01:/var/lib/kubelet#
root@controlplane:~# kubectl get nodes
NAME STATUS ROLES AGE VERSION
controlplane Ready control-plane,master 31m v1.20.0
node01 NotReady <none> 30m v1.20.0
root@controlplane:~#
fix kubelet service.
root@controlplane:~# kubectl get nodes
NAME STATUS ROLES AGE VERSION
controlplane Ready control-plane,master 38m v1.20.0
node01 Ready <none> 38m v1.20.0
root@controlplane:~#
always use "--no-pager" option with journalctl to see full readable logs
root@node01:/etc/kubernetes/pki# journalctl -u kubelet --no-pager -f
Sep 29 00:35:56 node01 kubelet[16383]: E0929 00:35:56.152194 16383 eviction_manager.go:260] eviction manager: failed to get summary stats: failed to get node info: node "node01" not found
Sep 29 00:35:56 node01 kubelet[16383]: E0929 00:35:56.162151 16383 kubelet.go:2240] node "node01" not found
Sep 29 00:35:56 node01 kubelet[16383]: E0929 00:35:56.262354 16383 kubelet.go:2240] node "node01" not found
Sep 29 00:35:56 node01 kubelet[16383]: E0929 00:35:56.362600 16383 kubelet.go:2240] node "node01" not found
Sep 29 00:35:56 node01 kubelet[16383]: E0929 00:35:56.462875 16383 kubelet.go:2240] node "node01" not found
Sep 29 00:35:56 node01 kubelet[16383]: E0929 00:35:56.563084 16383 kubelet.go:2240] node "node01" not found
Sep 29 00:35:56 node01 kubelet[16383]: E0929 00:35:56.663298 16383 kubelet.go:2240] node "node01" not found
Sep 29 00:35:56 node01 kubelet[16383]: E0929 00:35:56.763502 16383 kubelet.go:2240] node "node01" not found
Sep 29 00:35:56 node01 kubelet[16383]: E0929 00:35:56.863697 16383 kubelet.go:2240] node "node01" not found
Sep 29 00:35:56 node01 kubelet[16383]: I0929 00:35:56.907813 16383 kubelet_node_status.go:71] Attempting to register node node01
Sep 29 00:35:56 node01 kubelet[16383]: E0929 00:35:56.909407 16383 kubelet_node_status.go:93] Unable to register node "node01" with API server: Post "https://controlplane:6553/api/v1/nodes": dial tcp 10.53.130.2:6553: connect: connection refused
Sep 29 00:35:56 node01 kubelet[16383]: E0929 00:35:56.963833 16383 kubelet.go:2240] node "node01" not found
Sep 29 00:35:57 node01 kubelet[16383]: E0929 00:35:57.064046 16383 kubelet.go:2240] node "node01" not found
kube-proxy
kube-proxy
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.
– cni-bin-dir: Kubelet probes this directory for plugins on startup
– network-plugin: The network plugin to use from cni-bin-dir. It must match the name reported by a plugin probed from the plugin directory.
DNS:
---------->
If you find CoreDNS pods in pending state first check network plugin is installed.
2. coredns pods have CrashLoopBackOff or Error state
If you have nodes that are running SELinux with an older version of Docker
you might experience a scenario where the coredns pods are not starting. \
To solve that you can try one of the following options:
a)Upgrade to a newer version of Docker.
b)Disable SELinux.
c)Modify the coredns deployment to set "allowPrivilegeEscalation to true":
kubectl -n kube-system get deployment coredns -o yaml | \
sed 's/allowPrivilegeEscalation: false/allowPrivilegeEscalation: true/g' | \
kubectl apply -f -
kubeproxy-failure
kubeproxy-failure
root@controlplane:/# kubectl get all -n triton
NAME READY STATUS RESTARTS AGE
pod/mysql 0/1 ContainerCreating 0 44s
pod/webapp-mysql-54db464f4f-jfg42 0/1 ContainerCreating 0 43s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/mysql ClusterIP 10.108.89.216 <none> 3306/TCP 44s
service/web-service NodePort 10.101.145.126 <none> 8080:30081/TCP 43s
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/webapp-mysql 0/1 1 0 43s
NAME DESIRED CURRENT READY AGE
replicaset.apps/webapp-mysql-54db464f4f 1 1 0 43s
root@controlplane:/#
root@controlplane:/etc/kubernetes/manifests# kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d '\n')"
serviceaccount/weave-net created
clusterrole.rbac.authorization.k8s.io/weave-net created
clusterrolebinding.rbac.authorization.k8s.io/weave-net created
role.rbac.authorization.k8s.io/weave-net created
rolebinding.rbac.authorization.k8s.io/weave-net created
daemonset.apps/weave-net created
root@controlplane:/etc/kubernetes/manifests#
root@controlplane:/etc/kubernetes/manifests# kubectl -n kube-system logs kube-proxy-cklbr
F0929 01:08:39.832255 1 server.go:490] failed complete: open /var/lib/kube-proxy/configuration.conf: no such file or directory
root@controlplane:/etc/kubernetes/manifests# kubectl get cm -n kube-system
NAME DATA AGE
coredns 1 66m
extension-apiserver-authentication 6 66m
kube-proxy 2 66m
kube-root-ca.crt 1 66m
kubeadm-config 2 66m
kubelet-config-1.20 1 66m
weave-net 0 66m
root@controlplane:/etc/kubernetes/manifests#
json_jq
json_jq
MacBook-Pro:11.Troubleshooting bharathdasaraju$ cat test.json | jq .[0]
"hi"
MacBook-Pro:11.Troubleshooting bharathdasaraju$ cat test.json | jq .[]
"hi"
"hello"
"test"
MacBook-Pro:11.Troubleshooting bharathdasaraju$ cat test.json | jq .[0,1,2]
"hi"
"hello"
"test"
MacBook-Pro:11.Troubleshooting bharathdasaraju$ cat test.json | jq .[0,2]
"hi"
"test"
MacBook-Pro:11.Troubleshooting bharathdasaraju$
---------------------------------------------------------------------------------------------------------->
MacBook-Pro:11.Troubleshooting bharathdasaraju$ cat test2.json | jq .vehicles
{
"car": {
"color": "blue",
"price": "$20,000"
},
"bus": {
"color": "white",
"price": "$120,000"
}
}
MacBook-Pro:11.Troubleshooting bharathdasaraju$ cat test2.json | jq .vehicles.car
{
"color": "blue",
"price": "$20,000"
}
MacBook-Pro:11.Troubleshooting bharathdasaraju$ cat test2.json | jq .vehicles.car.price
"$20,000"
MacBook-Pro:11.Troubleshooting bharathdasaraju$ cat test2.json | jq .vehicles.bus.price
"$120,000"
MacBook-Pro:11.Troubleshooting bharathdasaraju$
json_path
json_path
{
"property1": "value1",
"property2": "value2"
}
$.property1
--------------------------------->
{
"car": {
"color": "blue",
"price": "$20,000"
},
"bus": {
"color": "white",
"price": "$120,000"
}
}
$.bus
$.bus.price
---------------------------------------->
{
"vehicles": {
"car": {
"color": "blue",
"price": "$20,000"
},
"bus": {
"color": "white",
"price": "$120,000"
}
}
}
$.vehicles.car.price
---------------------------------------------------------->
{
"car": {
"color": "blue",
"price": "$20,000",
"wheels": [
{
"model": "KDJ39848T",
"location": "front-right"
},
{
"model": "MDJ39485DK",
"location": "front-left"
},
{
"model": "KCMDD3435K",
"location": "rear-right"
},
{
"model": "JJDH34234KK",
"location": "rear-left"
}
]
}
}
$.car.wheels
$.car.wheels[2]
$.car.wheels[2].model
---------------------------------------------------->
{
"employee": {
"name": "john",
"gender": "male",
"age": 24,
"address": {
"city": "edison",
"state": "new jersey",
"country": "united states"
},
"payslips": [
{
"month": "june",
"amount": 1400
},
{
"month": "july",
"amount": 2400
},
{
"month": "august",
"amount": 3400
}
]
}
}
$.employee.payslips
----------------------------------->
{
"prizes": [
{
"year": "2018",
"category": "physics",
"overallMotivation": "\"for groundbreaking inventions in the field of laser physics\"",
"laureates": [
{
"id": "960",
"firstname": "Arthur",
"surname": "Ashkin",
"motivation": "\"for the optical tweezers and their application to biological systems\"",
"share": "2"
},
{
"id": "961",
"firstname": "Gérard",
"surname": "Mourou",
"motivation": "\"for their method of generating high-intensity, ultra-short optical pulses\"",
"share": "4"
},
{
"id": "962",
"firstname": "Donna",
"surname": "Strickland",
"motivation": "\"for their method of generating high-intensity, ultra-short optical pulses\"",
"share": "4"
}
]
},
{
"year": "2018",
"category": "chemistry",
"laureates": [
{
"id": "963",
"firstname": "Frances H.",
"surname": "Arnold",
"motivation": "\"for the directed evolution of enzymes\"",
"share": "2"
},
{
"id": "964",
"firstname": "George P.",
"surname": "Smith",
"motivation": "\"for the phage display of peptides and antibodies\"",
"share": "4"
},
{
"id": "965",
"firstname": "Sir Gregory P.",
"surname": "Winter",
"motivation": "\"for the phage display of peptides and antibodies\"",
"share": "4"
}
]
},
{
"year": "2018",
"category": "medicine",
"laureates": [
{
"id": "958",
"firstname": "James P.",
"surname": "Allison",
"motivation": "\"for their discovery of cancer therapy by inhibition of negative immune regulation\"",
"share": "2"
},
{
"id": "959",
"firstname": "Tasuku",
"surname": "Honjo",
"motivation": "\"for their discovery of cancer therapy by inhibition of negative immune regulation\"",
"share": "2"
}
]
},
{
"year": "2018",
"category": "peace",
"laureates": [
{
"id": "966",
"firstname": "Denis",
"surname": "Mukwege",
"motivation": "\"for their efforts to end the use of sexual violence as a weapon of war and armed conflict\"",
"share": "2"
},
{
"id": "967",
"firstname": "Nadia",
"surname": "Murad",
"motivation": "\"for their efforts to end the use of sexual violence as a weapon of war and armed conflict\"",
"share": "2"
}
]
},
{
"year": "2018",
"category": "economics",
"laureates": [
{
"id": "968",
"firstname": "William D.",
"surname": "Nordhaus",
"motivation": "\"for integrating climate change into long-run macroeconomic analysis\"",
"share": "2"
},
{
"id": "969",
"firstname": "Paul M.",
"surname": "Romer",
"motivation": "\"for integrating technological innovations into long-run macroeconomic analysis\"",
"share": "2"
}
]
},
{
"year": "2014",
"category": "peace",
"laureates": [
{
"id": "913",
"firstname": "Kailash",
"surname": "Satyarthi",
"motivation": "\"for their struggle against the suppression of children and young people and for the right of all children to education\"",
"share": "2"
},
{
"id": "914",
"firstname": "Malala",
"surname": "Yousafzai",
"motivation": "\"for their struggle against the suppression of children and young people and for the right of all children to education\"",
"share": "2"
}
]
},
{
"year": "2017",
"category": "physics",
"laureates": [
{
"id": "941",
"firstname": "Rainer",
"surname": "Weiss",
"motivation": "\"for decisive contributions to the LIGO detector and the observation of gravitational waves\"",
"share": "2"
},
{
"id": "942",
"firstname": "Barry C.",
"surname": "Barish",
"motivation": "\"for decisive contributions to the LIGO detector and the observation of gravitational waves\"",
"share": "4"
},
{
"id": "943",
"firstname": "Kip S.",
"surname": "Thorne",
"motivation": "\"for decisive contributions to the LIGO detector and the observation of gravitational waves\"",
"share": "4"
}
]
},
{
"year": "2017",
"category": "chemistry",
"laureates": [
{
"id": "944",
"firstname": "Jacques",
"surname": "Dubochet",
"motivation": "\"for developing cryo-electron microscopy for the high-resolution structure determination of biomolecules in solution\"",
"share": "3"
},
{
"id": "945",
"firstname": "Joachim",
"surname": "Frank",
"motivation": "\"for developing cryo-electron microscopy for the high-resolution structure determination of biomolecules in solution\"",
"share": "3"
},
{
"id": "946",
"firstname": "Richard",
"surname": "Henderson",
"motivation": "\"for developing cryo-electron microscopy for the high-resolution structure determination of biomolecules in solution\"",
"share": "3"
}
]
},
{
"year": "2017",
"category": "medicine",
"laureates": [
{
"id": "938",
"firstname": "Jeffrey C.",
"surname": "Hall",
"motivation": "\"for their discoveries of molecular mechanisms controlling the circadian rhythm\"",
"share": "3"
},
{
"id": "939",
"firstname": "Michael",
"surname": "Rosbash",
"motivation": "\"for their discoveries of molecular mechanisms controlling the circadian rhythm\"",
"share": "3"
},
{
"id": "940",
"firstname": "Michael W.",
"surname": "Young",
"motivation": "\"for their discoveries of molecular mechanisms controlling the circadian rhythm\"",
"share": "3"
}
]
}
]
}
$.prizes[5].laureates[1]
$.prizes[?(@.year==2014)].laureates[*].name
----------------------------------------------------->
[
"car",
"bus",
"truck",
"bike"
]
$[0]
$[0,3]
----------------------------->
{
"property1": "value1",
"property2": "value2"
}
$.*
jsonpath_queries
jsonpath_queries
MacBook-Pro:11.Troubleshooting bharathdasaraju$ kubectl get nodes -o wide
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
minikube Ready control-plane,master 25d v1.20.2 192.168.49.2 <none> Ubuntu 20.04.2 LTS 5.4.39-linuxkit docker://20.10.6
MacBook-Pro:11.Troubleshooting bharathdasaraju$
MacBook-Pro:11.Troubleshooting bharathdasaraju$ kubectl get nodes -o json | jq
{
"apiVersion": "v1",
"items": [
{
"apiVersion": "v1",
"kind": "Node",
"metadata": {
"annotations": {
"kubeadm.alpha.kubernetes.io/cri-socket": "/var/run/dockershim.sock",
"node.alpha.kubernetes.io/ttl": "0",
"volumes.kubernetes.io/controller-managed-attach-detach": "true"
},
"creationTimestamp": "2021-09-04T06:52:20Z",
"labels": {
"beta.kubernetes.io/arch": "amd64",
"beta.kubernetes.io/os": "linux",
"color": "blue",
"kubernetes.io/arch": "amd64",
"kubernetes.io/hostname": "minikube",
"kubernetes.io/os": "linux",
"minikube.k8s.io/commit": "c61663e942ec43b20e8e70839dcca52e44cd85ae",
"minikube.k8s.io/name": "minikube",
"minikube.k8s.io/updated_at": "2021_09_04T14_52_27_0700",
"minikube.k8s.io/version": "v1.20.0",
"node-role.kubernetes.io/control-plane": "",
"node-role.kubernetes.io/master": "",
"size": "Large"
},
"managedFields": [
{
"apiVersion": "v1",
"fieldsType": "FieldsV1",
"fieldsV1": {
"f:metadata": {
"f:annotations": {
"f:kubeadm.alpha.kubernetes.io/cri-socket": {}
},
"f:labels": {
"f:node-role.kubernetes.io/control-plane": {},
"f:node-role.kubernetes.io/master": {}
}
}
},
"manager": "kubeadm",
"operation": "Update",
"time": "2021-09-04T06:52:25Z"
},
{
"apiVersion": "v1",
"fieldsType": "FieldsV1",
"fieldsV1": {
"f:metadata": {
"f:labels": {
"f:color": {},
"f:minikube.k8s.io/commit": {},
"f:minikube.k8s.io/name": {},
"f:minikube.k8s.io/updated_at": {},
"f:minikube.k8s.io/version": {},
"f:size": {}
}
}
},
"manager": "kubectl-label",
"operation": "Update",
"time": "2021-09-17T23:00:31Z"
},
{
"apiVersion": "v1",
"fieldsType": "FieldsV1",
"fieldsV1": {
"f:metadata": {
"f:annotations": {
"f:node.alpha.kubernetes.io/ttl": {}
}
},
"f:spec": {
"f:podCIDR": {},
"f:podCIDRs": {
".": {},
"v:\"10.244.0.0/24\"": {}
}
}
},
"manager": "kube-controller-manager",
"operation": "Update",
"time": "2021-09-24T12:52:22Z"
},
{
"apiVersion": "v1",
"fieldsType": "FieldsV1",
"fieldsV1": {
"f:metadata": {
"f:annotations": {
".": {},
"f:volumes.kubernetes.io/controller-managed-attach-detach": {}
},
"f:labels": {
".": {},
"f:beta.kubernetes.io/arch": {},
"f:beta.kubernetes.io/os": {},
"f:kubernetes.io/arch": {},
"f:kubernetes.io/hostname": {},
"f:kubernetes.io/os": {}
}
},
"f:status": {
"f:addresses": {
".": {},
"k:{\"type\":\"Hostname\"}": {
".": {},
"f:address": {},
"f:type": {}
},
"k:{\"type\":\"InternalIP\"}": {
".": {},
"f:address": {},
"f:type": {}
}
},
"f:allocatable": {
".": {},
"f:cpu": {},
"f:ephemeral-storage": {},
"f:hugepages-1Gi": {},
"f:hugepages-2Mi": {},
"f:memory": {},
"f:pods": {}
},
"f:capacity": {
".": {},
"f:cpu": {},
"f:ephemeral-storage": {},
"f:hugepages-1Gi": {},
"f:hugepages-2Mi": {},
"f:memory": {},
"f:pods": {}
},
"f:conditions": {
".": {},
"k:{\"type\":\"DiskPressure\"}": {
".": {},
"f:lastHeartbeatTime": {},
"f:lastTransitionTime": {},
"f:message": {},
"f:reason": {},
"f:status": {},
"f:type": {}
},
"k:{\"type\":\"MemoryPressure\"}": {
".": {},
"f:lastHeartbeatTime": {},
"f:lastTransitionTime": {},
"f:message": {},
"f:reason": {},
"f:status": {},
"f:type": {}
},
"k:{\"type\":\"PIDPressure\"}": {
".": {},
"f:lastHeartbeatTime": {},
"f:lastTransitionTime": {},
"f:message": {},
"f:reason": {},
"f:status": {},
"f:type": {}
},
"k:{\"type\":\"Ready\"}": {
".": {},
"f:lastHeartbeatTime": {},
"f:lastTransitionTime": {},
"f:message": {},
"f:reason": {},
"f:status": {},
"f:type": {}
}
},
"f:daemonEndpoints": {
"f:kubeletEndpoint": {
"f:Port": {}
}
},
"f:images": {},
"f:nodeInfo": {
"f:architecture": {},
"f:bootID": {},
"f:containerRuntimeVersion": {},
"f:kernelVersion": {},
"f:kubeProxyVersion": {},
"f:kubeletVersion": {},
"f:machineID": {},
"f:operatingSystem": {},
"f:osImage": {},
"f:systemUUID": {}
}
}
},
"manager": "kubelet",
"operation": "Update",
"time": "2021-09-24T12:52:32Z"
},
{
"apiVersion": "v1",
"fieldsType": "FieldsV1",
"fieldsV1": {
"f:status": {
"f:conditions": {
"k:{\"type\":\"NetworkUnavailable\"}": {
".": {},
"f:lastHeartbeatTime": {},
"f:lastTransitionTime": {},
"f:message": {},
"f:reason": {},
"f:status": {},
"f:type": {}
}
}
}
},
"manager": "kube-utils",
"operation": "Update",
"time": "2021-09-27T07:00:54Z"
}
],
"name": "minikube",
"resourceVersion": "201862",
"uid": "c2ab7942-ba64-4e3f-b6e3-54f11e83082d"
},
"spec": {
"podCIDR": "10.244.0.0/24",
"podCIDRs": [
"10.244.0.0/24"
]
},
"status": {
"addresses": [
{
"address": "192.168.49.2",
"type": "InternalIP"
},
{
"address": "minikube",
"type": "Hostname"
}
],
"allocatable": {
"cpu": "2",
"ephemeral-storage": "61255492Ki",
"hugepages-1Gi": "0",
"hugepages-2Mi": "0",
"memory": "2035604Ki",
"pods": "110"
},
"capacity": {
"cpu": "2",
"ephemeral-storage": "61255492Ki",
"hugepages-1Gi": "0",
"hugepages-2Mi": "0",
"memory": "2035604Ki",
"pods": "110"
},
"conditions": [
{
"lastHeartbeatTime": "2021-09-29T08:05:47Z",
"lastTransitionTime": "2021-09-29T08:05:47Z",
"message": "Weave pod has set this",
"reason": "WeaveIsUp",
"status": "False",
"type": "NetworkUnavailable"
},
{
"lastHeartbeatTime": "2021-09-29T08:05:28Z",
"lastTransitionTime": "2021-09-24T12:52:32Z",
"message": "kubelet has sufficient memory available",
"reason": "KubeletHasSufficientMemory",
"status": "False",
"type": "MemoryPressure"
},
{
"lastHeartbeatTime": "2021-09-29T08:05:28Z",
"lastTransitionTime": "2021-09-24T12:52:32Z",
"message": "kubelet has no disk pressure",
"reason": "KubeletHasNoDiskPressure",
"status": "False",
"type": "DiskPressure"
},
{
"lastHeartbeatTime": "2021-09-29T08:05:28Z",
"lastTransitionTime": "2021-09-24T12:52:32Z",
"message": "kubelet has sufficient PID available",
"reason": "KubeletHasSufficientPID",
"status": "False",
"type": "PIDPressure"
},
{
"lastHeartbeatTime": "2021-09-29T08:05:28Z",
"lastTransitionTime": "2021-09-24T12:52:32Z",
"message": "kubelet is posting ready status",
"reason": "KubeletReady",
"status": "True",
"type": "Ready"
}
],
"daemonEndpoints": {
"kubeletEndpoint": {
"Port": 10250
}
},
"images": [
{
"names": [
"k8s.gcr.io/etcd@sha256:4ad90a11b55313b182afc186b9876c8e891531b8db4c9bf1541953021618d0e2",
"k8s.gcr.io/etcd:3.4.13-0"
],
"sizeBytes": 253392289
},
{
"names": [
"kubernetesui/dashboard@sha256:7f80b5ba141bead69c4fee8661464857af300d7d7ed0274cf7beecedc00322e6",
"kubernetesui/dashboard:v2.1.0"
],
"sizeBytes": 225733746
},
{
"names": [
"nginx@sha256:853b221d3341add7aaadf5f81dd088ea943ab9c918766e295321294b035f3f3e",
"nginx:latest"
],
"sizeBytes": 133283279
},
{
"names": [
"<none>@<none>",
"<none>:<none>"
],
"sizeBytes": 133175493
},
{
"names": [
"k8s.gcr.io/kube-apiserver@sha256:465ba895d578fbc1c6e299e45689381fd01c54400beba9e8f1d7456077411411",
"k8s.gcr.io/kube-apiserver:v1.20.2"
],
"sizeBytes": 121669114
},
{
"names": [
"k8s.gcr.io/kube-proxy@sha256:326fe8a4508a5db91cf234c4867eff5ba458bc4107c2a7e15c827a74faa19be9",
"k8s.gcr.io/kube-proxy:v1.20.2"
],
"sizeBytes": 118400203
},
{
"names": [
"k8s.gcr.io/kube-controller-manager@sha256:842a071d4ad49b0018f7f7404ac8a4ddfc2bce2ce15b3f8131d89563fda36c9b",
"k8s.gcr.io/kube-controller-manager:v1.20.2"
],
"sizeBytes": 115852794
},
{
"names": [
"<none>@<none>",
"<none>:<none>"
],
"sizeBytes": 105408201
},
{
"names": [
"weaveworks/weave-kube@sha256:d797338e7beb17222e10757b71400d8471bdbd9be13b5da38ce2ebf597fb4e63",
"weaveworks/weave-kube:2.8.1"
],
"sizeBytes": 89037656
},
{
"names": [
"kodekloud/webapp-color@sha256:99c3821ea49b89c7a22d3eebab5c2e1ec651452e7675af243485034a72eb1423",
"kodekloud/webapp-color:latest"
],
"sizeBytes": 84848908
},
{
"names": [
"<none>@<none>",
"<none>:<none>"
],
"sizeBytes": 84758750
},
{
"names": [
"kodekloud/event-simulator@sha256:1e3e9c72136bbc76c96dd98f29c04f298c3ae241c7d44e2bf70bcc209b030bf9",
"kodekloud/event-simulator:latest"
],
"sizeBytes": 78221917
},
{
"names": [
"ubuntu@sha256:9d6a8699fb5c9c39cf08a0871bd6219f0400981c570894cd8cbea30d3424a31f",
"ubuntu:latest"
],
"sizeBytes": 72776725
},
{
"names": [
"k8s.gcr.io/metrics-server/metrics-server@sha256:dbc33d7d35d2a9cc5ab402005aa7a0d13be6192f3550c7d42cba8d2d5e3a5d62"
],
"sizeBytes": 60547543
},
{
"names": [
"k8s.gcr.io/kube-scheduler@sha256:304b3d70497bd62498f19f82f9ef164d38948e5ae94966690abfe9d1858867e2",
"k8s.gcr.io/kube-scheduler:v1.20.2"
],
"sizeBytes": 46384634
},
{
"names": [
"k8s.gcr.io/coredns@sha256:73ca82b4ce829766d4f1f10947c3a338888f876fbed0540dc849c89ff256e90c",
"k8s.gcr.io/coredns:1.7.0"
],
"sizeBytes": 45227747
},
{
"names": [
"weaveworks/weave-npc@sha256:38d3e30a97a2260558f8deb0fc4c079442f7347f27c86660dbfc8ca91674f14c",
"weaveworks/weave-npc:2.8.1"
],
"sizeBytes": 39273789
},
{
"names": [
"kubernetesui/metrics-scraper@sha256:555981a24f184420f3be0c79d4efb6c948a85cfce84034f85a563f4151a81cbf",
"kubernetesui/metrics-scraper:v1.0.4"
],
"sizeBytes": 36937728
},
{
"names": [
"gcr.io/k8s-minikube/storage-provisioner@sha256:18eb69d1418e854ad5a19e399310e52808a8321e4c441c1dddad8977a0d7a944",
"gcr.io/k8s-minikube/storage-provisioner:v5"
],
"sizeBytes": 31465472
},
{
"names": [
"busybox@sha256:52f73a0a43a16cf37cd0720c90887ce972fe60ee06a687ee71fb93a7ca601df7",
"busybox:latest"
],
"sizeBytes": 1235724
},
{
"names": [
"k8s.gcr.io/pause@sha256:927d98197ec1141a368550822d18fa1c60bdae27b78b0c004f705f548c07814f",
"k8s.gcr.io/pause:3.2"
],
"sizeBytes": 682696
}
],
"nodeInfo": {
"architecture": "amd64",
"bootID": "ec127cba-1d71-4eda-9296-fe1fe4abb570",
"containerRuntimeVersion": "docker://20.10.6",
"kernelVersion": "5.4.39-linuxkit",
"kubeProxyVersion": "v1.20.2",
"kubeletVersion": "v1.20.2",
"machineID": "822f5ed6656e44929f6c2cc5d6881453",
"operatingSystem": "linux",
"osImage": "Ubuntu 20.04.2 LTS",
"systemUUID": "182b1b5d-793c-4026-88b4-599941ba1cae"
}
}
}
],
"kind": "List",
"metadata": {
"resourceVersion": "",
"selfLink": ""
}
}
MacBook-Pro:11.Troubleshooting bharathdasaraju$
MacBook-Pro:11.Troubleshooting bharathdasaraju$ kubectl get nodes -o=jsonpath='{.items[*].metadata.name}'
minikube
MacBook-Pro:11.Troubleshooting bharathdasaraju$
MacBook-Pro:11.Troubleshooting bharathdasaraju$ kubectl get nodes -o=jsonpath='{.items[*].status.nodeInfo}'
{"architecture":"amd64","bootID":"ec127cba-1d71-4eda-9296-fe1fe4abb570","containerRuntimeVersion":"docker://20.10.6","kernelVersion":"5.4.39-linuxkit","kubeProxyVersion":"v1.20.2","kubeletVersion":"v1.20.2","machineID":"822f5ed6656e44929f6c2cc5d6881453","operatingSystem":"linux","osImage":"Ubuntu 20.04.2 LTS","systemUUID":"182b1b5d-793c-4026-88b4-599941ba1cae"}
MacBook-Pro:11.Troubleshooting bharathdasaraju$ kubectl get nodes -o=jsonpath='{.items[*].status.nodeInfo.architecture}'
amd64
MacBook-Pro:11.Troubleshooting bharathdasaraju$
amd64MacBook-Pro:11.Troubleshooting bharathdasaraju$ kubectl get nodes -o=jsonpath='{.items[*].status.capacity}'
{"cpu":"2","ephemeral-storage":"61255492Ki","hugepages-1Gi":"0","hugepages-2Mi":"0","memory":"2035604Ki","pods":"110"}
MacBook-Pro:11.Troubleshooting bharathdasaraju$
MacBook-Pro:11.Troubleshooting bharathdasaraju$ kubectl get nodes -o=jsonpath='{.items[*].status.capacity.cpu}'
2
MacBook-Pro:11.Troubleshooting bharathdasaraju$ kubectl get nodes -o=jsonpath='{.items[*].metadata.name}{.items[*].status.capacity.cpu}'
minikube2
MacBook-Pro:11.Troubleshooting bharathdasaraju$ kubectl get nodes -o=jsonpath='{.items[*].metadata.name} {.items[*].status.capacity.cpu}'
minikube 2
MacBook-Pro:11.Troubleshooting bharathdasaraju$
loops in json path:
------------------------>
MacBook-Pro:11.Troubleshooting bharathdasaraju$ kubectl get nodes -o=jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.status.capacity.cpu}{"\n"}{end}'
minikube 2
MacBook-Pro:11.Troubleshooting bharathdasaraju$
cutom columns in jsonpath:
--------------------------------->
acBook-Pro:11.Troubleshooting bharathdasaraju$ kubectl get nodes -o=custom-columns=NODE:.metadata.name
NODE
minikube
MacBook-Pro:11.Troubleshooting bharathdasaraju$
MacBook-Pro:11.Troubleshooting bharathdasaraju$ kubectl get nodes -o=custom-columns=NODE:.metadata.name,CPU:.status.capacity.cpu
NODE CPU
minikube 2
MacBook-Pro:11.Troubleshooting bharathdasaraju$
kubectl with --sort-by options:
----------------------------------------------------------------------------------------------------->
MacBook-Pro:11.Troubleshooting bharathdasaraju$ kubectl get nodes --sort-by=.metadata.name
NAME STATUS ROLES AGE VERSION
minikube Ready control-plane,master 25d v1.20.2
MacBook-Pro:11.Troubleshooting bharathdasaraju$ kubectl get nodes --sort-by=.status.capacity.cpu
NAME STATUS ROLES AGE VERSION
minikube Ready control-plane,master 25d v1.20.2
MacBook-Pro:11.Troubleshooting bharathdasaraju$
Question:
------------------------->
The order of container could be different.
The redis-container need not be the second container all the time.
So, re-develop a JSON PATH query to get the restart count of redis-container,
but this time use a criteria/condition to get the restart count of the container with the container name redis-container
Answer:
--------------------------->
$.status.containerStatuses[?(@.name == 'redis-container')].restartCount
{
"apiVersion": "v1",
"kind": "Pod",
"metadata": {
"name": "nginx-pod",
"namespace": "default"
},
"spec": {
"containers": [
{
"image": "nginx:alpine",
"name": "nginx"
},
{
"image": "redis:alpine",
"name": "redis-container"
}
],
"nodeName": "node01"
},
"status": {
"conditions": [
{
"lastProbeTime": null,
"lastTransitionTime": "2019-06-13T05:34:09Z",
"status": "True",
"type": "Initialized"
},
{
"lastProbeTime": null,
"lastTransitionTime": "2019-06-13T05:34:09Z",
"status": "True",
"type": "PodScheduled"
}
],
"containerStatuses": [
{
"image": "nginx:alpine",
"name": "nginx",
"ready": false,
"restartCount": 4,
"state": {
"waiting": {
"reason": "ContainerCreating"
}
}
},
{
"image": "redis:alpine",
"name": "redis-container",
"ready": false,
"restartCount": 2,
"state": {
"waiting": {
"reason": "ContainerCreating"
}
}
}
],
"hostIP": "172.17.0.75",
"phase": "Pending",
"qosClass": "BestEffort",
"startTime": "2019-06-13T05:34:09Z"
}
}
------------------------------------------------------------------------------------------->
[
{
"apiVersion": "v1",
"kind": "Pod",
"metadata": {
"name": "web-pod-1",
"namespace": "default"
},
"spec": {
"containers": [
{
"image": "nginx:alpine",
"name": "nginx"
}
],
"nodeName": "node01"
}
},
{
"apiVersion": "v1",
"kind": "Pod",
"metadata": {
"name": "web-pod-2",
"namespace": "default"
},
"spec": {
"containers": [
{
"image": "nginx:alpine",
"name": "nginx"
}
],
"nodeName": "node02"
}
},
{
"apiVersion": "v1",
"kind": "Pod",
"metadata": {
"name": "web-pod-3",
"namespace": "default"
},
"spec": {
"containers": [
{
"image": "nginx:alpine",
"name": "nginx"
}
],
"nodeName": "node01"
}
},
{
"apiVersion": "v1",
"kind": "Pod",
"metadata": {
"name": "web-pod-4",
"namespace": "default"
},
"spec": {
"containers": [
{
"image": "nginx:alpine",
"name": "nginx"
}
],
"nodeName": "node01"
}
},
{
"apiVersion": "v1",
"kind": "Pod",
"metadata": {
"name": "db-pod-1",
"namespace": "default"
},
"spec": {
"containers": [
{
"image": "mysql",
"name": "mysql"
}
],
"nodeName": "node01"
}
}
]
Develop a JSON PATH query to get all pod names.
$[*].metadata.name
{
"kind": "Config",
"apiVersion": "v1",
"preferences": {},
"clusters": [
{
"name": "development",
"cluster": {
"server": "KUBE_ADDRESS",
"certificate-authority": "/etc/kubernetes/pki/ca.crt"
}
},
{
"name": "kubernetes-on-aws",
"cluster": {
"server": "KUBE_ADDRESS",
"certificate-authority": "/etc/kubernetes/pki/ca.crt"
}
},
{
"name": "production",
"cluster": {
"server": "KUBE_ADDRESS",
"certificate-authority": "/etc/kubernetes/pki/ca.crt"
}
},
{
"name": "test-cluster-1",
"cluster": {
"server": "KUBE_ADDRESS",
"certificate-authority": "/etc/kubernetes/pki/ca.crt"
}
}
],
"users": [
{
"name": "aws-user",
"user": {
"client-certificate": "/etc/kubernetes/pki/users/aws-user/aws-user.crt",
"client-key": "/etc/kubernetes/pki/users/aws-user/aws-user.key"
}
},
{
"name": "dev-user",
"user": {
"client-certificate": "/etc/kubernetes/pki/users/dev-user/developer-user.crt",
"client-key": "/etc/kubernetes/pki/users/dev-user/dev-user.key"
}
},
{
"name": "test-user",
"user": {
"client-certificate": "/etc/kubernetes/pki/users/test-user/test-user.crt",
"client-key": "/etc/kubernetes/pki/users/test-user/test-user.key"
}
}
],
"contexts": [
{
"name": "aws-user@kubernetes-on-aws",
"context": {
"cluster": "kubernetes-on-aws",
"user": "aws-user"
}
},
{
"name": "research",
"context": {
"cluster": "test-cluster-1",
"user": "dev-user"
}
},
{
"name": "test-user@development",
"context": {
"cluster": "development",
"user": "test-user"
}
},
{
"name": "test-user@production",
"context": {
"cluster": "production",
"user": "test-user"
}
}
],
"current-context": "test-user@development"
}
Develop a JSON PATH query to get all user names.
$.users[*].name
jsonpath_k8s
jsonpath_k8s
root@controlplane:~# kubectl get nodes -o=jsonpath='{.items[*].metadata.name}'
controlplane node01
root@controlplane:~#
root@controlplane:~# kubectl get nodes -o=jsonpath='{.items[*].metadata.name}' > /opt/outputs/node_names.txt
root@controlplane:~# cat /opt/outputs/node_names.txt
controlplane node01
root@controlplane:~#
root@controlplane:~# kubectl get nodes -o jsonpath='{.items[*].status.nodeInfo.osImage}' > /opt/outputs/nodes_os.txt
root@controlplane:~# kubectl get nodes -o jsonpath='{.items[*].status.nodeInfo.osImage}'
Ubuntu 18.04.5 LTS Ubuntu 18.04.5 LTS
root@controlplane:~#
root@controlplane:~# kubectl config view --kubeconfig=/root/my-kube-config
apiVersion: v1
clusters:
- cluster:
certificate-authority: /etc/kubernetes/pki/ca.crt
server: KUBE_ADDRESS
name: development
- cluster:
certificate-authority: /etc/kubernetes/pki/ca.crt
server: KUBE_ADDRESS
name: kubernetes-on-aws
- cluster:
certificate-authority: /etc/kubernetes/pki/ca.crt
server: KUBE_ADDRESS
name: production
- cluster:
certificate-authority: /etc/kubernetes/pki/ca.crt
server: KUBE_ADDRESS
name: test-cluster-1
contexts:
- context:
cluster: kubernetes-on-aws
user: aws-user
name: aws-user@kubernetes-on-aws
- context:
cluster: test-cluster-1
user: dev-user
name: research
- context:
cluster: development
user: test-user
name: test-user@development
- context:
cluster: production
user: test-user
name: test-user@production
current-context: test-user@development
kind: Config
preferences: {}
users:
- name: aws-user
user:
client-certificate: /etc/kubernetes/pki/users/aws-user/aws-user.crt
client-key: /etc/kubernetes/pki/users/aws-user/aws-user.key
- name: dev-user
user:
client-certificate: /etc/kubernetes/pki/users/dev-user/developer-user.crt
client-key: /etc/kubernetes/pki/users/dev-user/dev-user.key
- name: test-user
user:
client-certificate: /etc/kubernetes/pki/users/test-user/test-user.crt
client-key: /etc/kubernetes/pki/users/test-user/test-user.key
root@controlplane:~#
root@controlplane:~# kubectl config view --kubeconfig=/root/my-kube-config -o jsonpath="{.users[*].name}"
aws-user dev-user test-user
root@controlplane:~#
root@controlplane:~# kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pv-log-1 100Mi RWX Retain Available 15m
pv-log-2 200Mi RWX Retain Available 15m
pv-log-3 300Mi RWX Retain Available 15m
pv-log-4 40Mi RWX Retain Available 15m
root@controlplane:~#
root@controlplane:~# kubectl get pv --sort-by=.spec.capacity.storage
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pv-log-4 40Mi RWX Retain Available 18m
pv-log-1 100Mi RWX Retain Available 18m
pv-log-2 200Mi RWX Retain Available 18m
pv-log-3 300Mi RWX Retain Available 18m
root@controlplane:~#
kubectl get pv --sort-by=.spec.capacity.storage -o=custom-columns=NAME:.metadata.name,CAPACITY:.spec.capacity.storage
root@controlplane:~# kubectl get pv --sort-by=.spec.capacity.storage -o=custom-columns=NAME:.metadata.name,CAPACITY:.spec.capacity.storage
NAME CAPACITY
pv-log-4 40Mi
pv-log-1 100Mi
pv-log-2 200Mi
pv-log-3 300Mi
root@controlplane:~#
root@controlplane:~# kubectl config view --kubeconfig=my-kube-config -o jsonpath="{.contexts[?(@.context.user=='aws-user')].name}"
aws-user@kubernetes-on-aws
root@controlplane:~#