chore(docs): Added Docs for Probes (#12)
* Added Docs for Probes Signed-off-by: Sayan Mondal <sayan@chaosnative.com> * Removing an extra page break Signed-off-by: Sayan Mondal <sayan@chaosnative.com> * EmbedMD check Signed-off-by: Sayan Mondal <sayan@chaosnative.com> * Resolving Spellchecker issue Signed-off-by: Sayan Mondal <sayan@chaosnative.com> * Resolving new Spellchecker issue Signed-off-by: Sayan Mondal <sayan@chaosnative.com>
This commit is contained in:
Sayan Mondal
GitHub
parent
750c9637f4
commit
55b97acad0
664
.wordlist.txt
664
.wordlist.txt
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@ -1,21 +1,653 @@
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||||||
gitOps
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accomodate
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||||||
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accomodated
|
||||||
|
ada
|
||||||
|
addon
|
||||||
|
Adminstator
|
||||||
|
afx
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||||||
|
airgapped
|
||||||
|
AKS
|
||||||
|
al
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||||||
|
allowedCapabilities
|
||||||
|
allowedHostPaths
|
||||||
|
allowedProfileNames
|
||||||
|
allowPrivilegeEscalation
|
||||||
|
amazonaws
|
||||||
|
amd
|
||||||
|
analytics
|
||||||
|
annotationCheck
|
||||||
|
annotationChecks
|
||||||
|
ansible
|
||||||
|
Ansible
|
||||||
|
api
|
||||||
|
apiextensions
|
||||||
|
apiGroup
|
||||||
|
apiGroups
|
||||||
|
apis
|
||||||
|
APIs
|
||||||
|
apiserver
|
||||||
|
apiVersion
|
||||||
|
AppArmor
|
||||||
|
appGroup
|
||||||
|
appinfo
|
||||||
|
appInfo
|
||||||
|
appkind
|
||||||
|
applabel
|
||||||
|
appLabels
|
||||||
|
appns
|
||||||
|
appResource
|
||||||
|
appResourceName
|
||||||
|
appVersion
|
||||||
|
arg
|
||||||
|
argo
|
||||||
|
ArgoCD
|
||||||
|
argoproj
|
||||||
|
argowf
|
||||||
|
args
|
||||||
|
AUT
|
||||||
|
auth
|
||||||
|
AUTH
|
||||||
|
autoscaler
|
||||||
|
Autoscaler
|
||||||
|
autoscaling
|
||||||
|
auxiliaryAppInfo
|
||||||
|
avc
|
||||||
|
AVC
|
||||||
|
awk
|
||||||
|
aws
|
||||||
|
awsregion
|
||||||
|
ba
|
||||||
|
backOff
|
||||||
|
baremetal
|
||||||
|
Baremetal
|
||||||
|
bd
|
||||||
|
BDD
|
||||||
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bfea
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||||||
|
blockcount
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||||||
|
blocksize
|
||||||
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bodyPath
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||||||
|
bool
|
||||||
|
BringYourOwnChaos
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||||||
|
busybox
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||||||
|
Busybox
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||||||
|
BYOC
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||||||
|
cassandra
|
||||||
|
cd
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||||||
|
cde
|
||||||
|
ce
|
||||||
|
Centric
|
||||||
|
chaoexperiment
|
||||||
|
ChaosChart
|
||||||
|
ChaosCharts
|
||||||
|
chaosec
|
||||||
|
chaosengine
|
||||||
|
ChaosEngine
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||||||
|
ChaosEngineCompleted
|
||||||
|
ChaosEngineInitialized
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||||||
|
chaosengines
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||||||
|
ChaosEngine's
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||||||
|
ChaosEngines
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||||||
|
ChaosEngineSpec
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||||||
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chaosexperiment
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||||||
|
ChaosExperiment
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||||||
|
chaosexperiments
|
||||||
|
ChaosExperiments
|
||||||
|
chaoshub
|
||||||
|
ChaosHub
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||||||
|
ChaosInject
|
||||||
|
chaoslib
|
||||||
|
ChaosOperator
|
||||||
|
ChaosPod
|
||||||
|
ChaosResourcesOperationFailed
|
||||||
|
chaosresult
|
||||||
|
ChaosResult
|
||||||
|
chaosresults
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||||||
|
ChaosResults
|
||||||
|
ChaosRunner
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||||||
|
chaosschedule
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||||||
|
ChaosSchedule
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||||||
|
ChaosScheduler
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||||||
|
chaosschedules
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||||||
|
chaosServiceAccount
|
||||||
|
chaosServiceAccounts
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||||||
|
chaosshedule
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||||||
|
chaostoolkit
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||||||
|
Chaostoolkit
|
||||||
|
ChaosToolKit
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||||||
|
chaosUID
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||||||
|
ChaosWorkflow
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||||||
|
ChaosWorkflows
|
||||||
|
charthub
|
||||||
|
chmod
|
||||||
|
chroot
|
||||||
|
ci
|
||||||
|
CLI
|
||||||
|
clientset
|
||||||
|
ClusterIP
|
||||||
|
clusterrole
|
||||||
|
clusterRole
|
||||||
|
ClusterRole
|
||||||
|
clusterrolebinding
|
||||||
|
ClusterRoleBinding
|
||||||
|
ClusterRoles
|
||||||
|
cmd
|
||||||
|
cmdProbe
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||||||
|
CmdProbe
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||||||
|
cmdProbes
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||||||
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CNXNB
|
||||||
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commmand
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||||||
|
comparator
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||||||
|
comparision
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||||||
|
config
|
||||||
|
configmap
|
||||||
|
configMap
|
||||||
|
ConfigMap
|
||||||
|
configmaps
|
||||||
|
configMaps
|
||||||
|
configs
|
||||||
|
connectto
|
||||||
|
ContainerCreating
|
||||||
|
containerd
|
||||||
|
containerPort
|
||||||
|
containerSecurityContext
|
||||||
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continer
|
||||||
|
coredns
|
||||||
|
coreDNS
|
||||||
|
CoreDns
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||||||
|
CoreDNS
|
||||||
|
corev
|
||||||
|
cp
|
||||||
|
cpu
|
||||||
|
Cpu
|
||||||
|
cr
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||||||
|
CrashLoopBackOff
|
||||||
|
crd
|
||||||
|
CRD
|
||||||
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crds
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||||||
|
CRDs
|
||||||
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CRI
|
||||||
|
crictl
|
||||||
|
crio
|
||||||
|
cron
|
||||||
|
cronjob
|
||||||
|
CRs
|
||||||
|
cstor
|
||||||
|
cStor
|
||||||
|
cstorpools
|
||||||
|
cstorvolumereplicas
|
||||||
|
customresourcedefinition
|
||||||
|
Customresourcedefinition
|
||||||
|
da
|
||||||
|
daemonset
|
||||||
|
daemonsets
|
||||||
|
datasource
|
||||||
|
dbname
|
||||||
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dbpassword
|
||||||
|
dbuser
|
||||||
|
debuggability
|
||||||
|
deletecollection
|
||||||
|
Deployable
|
||||||
|
deploymemt
|
||||||
|
deploymentconfig
|
||||||
|
deploymentconfigs
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||||||
|
Deplying
|
||||||
|
deprovision
|
||||||
|
dettached
|
||||||
|
dev
|
||||||
|
devguide
|
||||||
|
devops
|
||||||
|
DevOps
|
||||||
|
dns
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||||||
|
DNS
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||||||
|
downtimes
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||||||
|
downwardAPI
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||||||
|
ds
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||||||
|
DS
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||||||
|
DSL
|
||||||
|
du
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||||||
|
ebs
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||||||
|
EBS
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||||||
|
ec
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||||||
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efb
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||||||
|
EKS
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||||||
|
embedmd
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||||||
|
emptyDir
|
||||||
|
enbaledor
|
||||||
|
endTime
|
||||||
|
engineSpec
|
||||||
|
engineState
|
||||||
|
engineStatus
|
||||||
|
engineTemplateSpec
|
||||||
|
entrypoint
|
||||||
|
env
|
||||||
|
EnvParseError
|
||||||
|
ENVs
|
||||||
|
EoT
|
||||||
|
EOT
|
||||||
|
errored
|
||||||
|
et
|
||||||
|
eth
|
||||||
|
ethernet
|
||||||
|
eventrouter
|
||||||
|
exampleFile
|
||||||
|
exe
|
||||||
|
execing
|
||||||
|
Execing
|
||||||
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executionTime
|
||||||
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experimentannotation
|
||||||
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experimentannotations
|
||||||
|
ExperimentDependencyCheck
|
||||||
|
experimentImage
|
||||||
|
experimentImagePullSecrets
|
||||||
|
ExperimentNotFound
|
||||||
|
experimentstatus
|
||||||
|
Experimentstatus
|
||||||
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experimet
|
||||||
|
expr
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||||||
|
failedRuns
|
||||||
|
failstep
|
||||||
|
faq
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||||||
|
Fdocker
|
||||||
|
fff
|
||||||
|
fieldPath
|
||||||
|
fieldRef
|
||||||
|
fieldSelector
|
||||||
|
filesystem
|
||||||
|
FILESYSTEM
|
||||||
|
Fillup
|
||||||
|
finalizer
|
||||||
|
finalizers
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||||||
|
fluentd
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||||||
|
FluxCD
|
||||||
|
FQDN
|
||||||
|
frontend
|
||||||
|
Frun
|
||||||
|
fsGroup
|
||||||
|
Fvar
|
||||||
|
gaiaadm
|
||||||
|
gaiadocker
|
||||||
|
GC
|
||||||
|
gcloud
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||||||
|
GCloud
|
||||||
|
gcp
|
||||||
|
GCP
|
||||||
|
getstarted
|
||||||
|
gettingstarted
|
||||||
|
Gi
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||||||
|
GigaBytes
|
||||||
|
github
|
||||||
|
Github
|
||||||
|
githubusercontent
|
||||||
|
Gitlab
|
||||||
GitOps
|
GitOps
|
||||||
gitops
|
gitops
|
||||||
|
gke
|
||||||
|
GKE
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||||||
|
gprasath
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||||||
|
grafana
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||||||
|
Grafana
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||||||
|
GVR
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||||||
|
hax
|
||||||
|
heptio
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||||||
|
hostFileVolumes
|
||||||
|
hostIPC
|
||||||
|
hostname
|
||||||
|
hostNetwork
|
||||||
|
hostPath
|
||||||
|
hostPID
|
||||||
|
htop
|
||||||
|
http
|
||||||
|
httpProbe
|
||||||
|
HTTPProbe
|
||||||
|
https
|
||||||
|
highlevel
|
||||||
|
iam
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||||||
|
iconColor
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||||||
|
IfNotPresent
|
||||||
|
iks
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||||||
|
imagePullPolicy
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||||||
|
imagePullSecret
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|
imagePullSecrets
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|
includedDays
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||||||
|
includedHours
|
||||||
|
inflight
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||||||
|
initialDelaySeconds
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||||||
|
insecureSkipVerify
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||||||
|
instace
|
||||||
|
instanceCount
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||||||
|
Integrations
|
||||||
|
io
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||||||
|
ip
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||||||
|
iproute
|
||||||
|
ips
|
||||||
|
IPS
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||||||
|
iSCSI
|
||||||
|
istgt
|
||||||
|
jiva
|
||||||
|
Jiva
|
||||||
|
jobCleanupPolicy
|
||||||
|
jobCleanUpPolicy
|
||||||
|
json
|
||||||
|
JSON
|
||||||
|
jsonpath
|
||||||
|
jt
|
||||||
|
kafka
|
||||||
|
keiko
|
||||||
|
keygen
|
||||||
|
keyspace
|
||||||
|
KEYSPACE
|
||||||
|
kh
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||||||
|
kiam
|
||||||
|
Kiam
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||||||
|
KinD
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|
Konvoy
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||||||
|
KOPS
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||||||
|
kube
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||||||
|
Kube
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||||||
|
kubeadm
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||||||
|
Kubeadm
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||||||
|
kubeconfig
|
||||||
|
KUBECONFIG
|
||||||
|
kubectl
|
||||||
|
kubelet
|
||||||
|
Kubelet
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||||||
|
kubernetes
|
||||||
Kubernetes
|
Kubernetes
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||||||
downtimes
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kubespray
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||||||
DevOps
|
Kubevirt
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||||||
SREs
|
Kudo
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||||||
CRDs
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KUDO
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||||||
ChaosHub
|
labelSelector
|
||||||
Kubernetes
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labelselectors
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||||||
toolset
|
latencies
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||||||
ChaosWorkflow
|
legendFormat
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||||||
analytics
|
libs
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||||||
ArgoCD
|
lifecycle
|
||||||
FluxCD
|
linux
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||||||
scalable
|
litmusbooks
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||||||
observability
|
litmuschaos
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||||||
ChaosWorkflows
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LitmusChaos
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||||||
|
litmuslib
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||||||
|
LitmusLib
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||||||
|
litmusresults
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||||||
|
liveness
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||||||
|
LIVENESS
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||||||
|
livenss
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||||||
|
lname
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||||||
|
LoadBalancer
|
||||||
|
localhost
|
||||||
|
LocalObjectReference
|
||||||
|
localpv
|
||||||
|
logrus
|
||||||
|
lossy
|
||||||
|
lqbw
|
||||||
|
lZ
|
||||||
|
matchLabels
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||||||
|
maya
|
||||||
|
mayadata
|
||||||
|
md
|
||||||
|
mebibytes
|
||||||
|
Mebibytes
|
||||||
|
MEBIBYTES
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||||||
|
metricset
|
||||||
|
mgmt
|
||||||
|
Microservice
|
||||||
microservices
|
microservices
|
||||||
CLI
|
minChaosInterval
|
||||||
|
Minikube
|
||||||
|
minio
|
||||||
|
mountPath
|
||||||
|
msg
|
||||||
|
MustRunAs
|
||||||
|
mv
|
||||||
|
myhtop
|
||||||
|
mysql
|
||||||
|
namespace
|
||||||
|
namespaced
|
||||||
|
Namespaced
|
||||||
|
namespaces
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||||||
|
ndm
|
||||||
|
netem
|
||||||
|
nfs
|
||||||
|
NFS
|
||||||
|
ng
|
||||||
|
nginx
|
||||||
|
nodename
|
||||||
|
nodeName
|
||||||
|
nodeport
|
||||||
|
NodePort
|
||||||
|
nodeselector
|
||||||
|
nodeSelector
|
||||||
|
NoExecute
|
||||||
|
notEqual
|
||||||
|
NotFound
|
||||||
|
notMatches
|
||||||
|
NotReady
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||||||
|
ns
|
||||||
|
observability
|
||||||
|
oc
|
||||||
|
OnChaos
|
||||||
|
oneof
|
||||||
|
oneOf
|
||||||
|
openebs
|
||||||
|
Openebs
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||||||
|
OpenEBS
|
||||||
|
OPENEBS
|
||||||
|
openshift
|
||||||
|
OpenShift
|
||||||
|
opensource
|
||||||
|
overlayed
|
||||||
|
params
|
||||||
|
passedRuns
|
||||||
|
pathPrefix
|
||||||
|
pdf
|
||||||
|
PERC
|
||||||
|
percona
|
||||||
|
persistentVolumeClaim
|
||||||
|
PersistentVolumeClaim
|
||||||
|
persistentvolumeclaims
|
||||||
|
persistentvolumes
|
||||||
|
persistentVolumes
|
||||||
|
pid
|
||||||
|
PID
|
||||||
|
pluggable
|
||||||
|
podSecurityContext
|
||||||
|
PodSecurityContext
|
||||||
|
podsecuritypolicies
|
||||||
|
PodSecurityPolicy
|
||||||
|
postchaos
|
||||||
|
powerfulseal
|
||||||
|
PowerfulSeal
|
||||||
|
poweroff
|
||||||
|
Poweroff
|
||||||
|
pre
|
||||||
|
prebuilt
|
||||||
|
prechaos
|
||||||
|
PreRequisites
|
||||||
|
privatekey
|
||||||
|
probeArtifact
|
||||||
|
ProbeArtifacts
|
||||||
|
probeName
|
||||||
|
probePollingInterval
|
||||||
|
probestatus
|
||||||
|
probesuccesspercentage
|
||||||
|
probeSuccessPercentage
|
||||||
|
probeTimeout
|
||||||
|
proc
|
||||||
|
prometheus
|
||||||
|
promProbe
|
||||||
|
promql
|
||||||
|
provisioner
|
||||||
|
Provisioner
|
||||||
|
PROVISIONER
|
||||||
|
ps
|
||||||
|
psp
|
||||||
|
PSP
|
||||||
|
ptr
|
||||||
|
pumba
|
||||||
|
Pumba
|
||||||
|
pushgateway
|
||||||
|
PV
|
||||||
|
pvc
|
||||||
|
PVs
|
||||||
|
py
|
||||||
|
PyYaml
|
||||||
|
queryPath
|
||||||
|
rbac
|
||||||
|
rdx
|
||||||
|
reaccessable
|
||||||
|
readOnlyRootFilesystem
|
||||||
|
redhat
|
||||||
|
refId
|
||||||
|
reframed
|
||||||
|
relook
|
||||||
|
repicas
|
||||||
|
replicaset
|
||||||
|
replicasets
|
||||||
|
replicationcontrollers
|
||||||
|
repo
|
||||||
|
resourceNames
|
||||||
|
ResourceRequirements
|
||||||
|
responseCode
|
||||||
|
restorecon
|
||||||
|
rlt
|
||||||
|
RMW
|
||||||
|
RoleBinding
|
||||||
|
roleRef
|
||||||
|
rollout
|
||||||
|
rollouts
|
||||||
|
rsa
|
||||||
|
RSA
|
||||||
|
RunAsAny
|
||||||
|
runAsUser
|
||||||
|
runcmd
|
||||||
|
runnerannotation
|
||||||
|
runnning
|
||||||
|
runProperties
|
||||||
|
runtime
|
||||||
|
runtimes
|
||||||
|
rw
|
||||||
|
RWM
|
||||||
|
sa
|
||||||
|
SBT
|
||||||
Scalability
|
Scalability
|
||||||
|
scalable
|
||||||
|
schedulable
|
||||||
|
scheduleState
|
||||||
|
scontext
|
||||||
|
sdb
|
||||||
|
sDem
|
||||||
|
sdk
|
||||||
|
seccomp
|
||||||
|
securityContext
|
||||||
|
selinux
|
||||||
|
seLinux
|
||||||
|
Selinux
|
||||||
|
SeLinux
|
||||||
|
SELinux
|
||||||
|
semodule
|
||||||
|
ServerAliveCountMax
|
||||||
|
ServerAliveInterval
|
||||||
|
serviceaccount
|
||||||
|
ServiceAccount
|
||||||
|
serviceAccountName
|
||||||
|
serviceaccounts
|
||||||
|
sfeyq
|
||||||
|
showIn
|
||||||
|
sig
|
||||||
|
SIGKILL
|
||||||
|
sirupsen
|
||||||
|
slc
|
||||||
|
sLO
|
||||||
|
SLOs
|
||||||
|
SoT
|
||||||
|
specifed
|
||||||
|
specificed
|
||||||
|
specifictions
|
||||||
|
sProbe
|
||||||
|
SRE
|
||||||
|
SREs
|
||||||
|
srw
|
||||||
|
SSHing
|
||||||
|
SSL
|
||||||
|
startTime
|
||||||
|
stateful
|
||||||
|
Stateful
|
||||||
|
statefulset
|
||||||
|
statefulsets
|
||||||
|
statusCheckTimeouts
|
||||||
|
stdout
|
||||||
|
stoppedRuns
|
||||||
|
storageclasses
|
||||||
|
stringData
|
||||||
|
sts
|
||||||
|
sudo
|
||||||
|
sumitnagal
|
||||||
|
superset
|
||||||
|
supplementalGroups
|
||||||
|
svc
|
||||||
|
SVC
|
||||||
|
SYS
|
||||||
|
systemctl
|
||||||
|
systemd
|
||||||
|
tagKeys
|
||||||
|
tc
|
||||||
|
tclass
|
||||||
|
tcontext
|
||||||
|
tcp
|
||||||
|
TCP
|
||||||
|
te
|
||||||
|
terminationGracePeriodSeconds
|
||||||
|
testcase
|
||||||
|
testfile
|
||||||
|
textFormat
|
||||||
|
th
|
||||||
|
Timeformat
|
||||||
|
timeRange
|
||||||
|
TimeStamp
|
||||||
|
titleFormat
|
||||||
|
TKGi
|
||||||
|
TODO
|
||||||
|
tolerations
|
||||||
|
Tolerations
|
||||||
|
toolset
|
||||||
|
TSDB
|
||||||
|
TSDBs
|
||||||
|
tunable
|
||||||
|
tunables
|
||||||
|
Tunables
|
||||||
|
ubuntu
|
||||||
|
uc
|
||||||
|
ui
|
||||||
|
UI
|
||||||
|
UID
|
||||||
|
un
|
||||||
|
uncordon
|
||||||
|
uninstallation
|
||||||
|
Uninstallation
|
||||||
|
unix
|
||||||
|
unschedulable
|
||||||
|
uptime
|
||||||
|
upto
|
||||||
|
URIs
|
||||||
|
url
|
||||||
|
usecases
|
||||||
|
usr
|
||||||
|
utils
|
||||||
|
valueFrom
|
||||||
|
VMs
|
||||||
|
VMware
|
||||||
|
volumeMount
|
||||||
|
WithError
|
||||||
|
WebUI
|
||||||
|
wordpress
|
||||||
|
workDays
|
||||||
|
workHours
|
||||||
|
wp
|
||||||
|
yaml
|
||||||
|
yml
|
||||||
|
zk
|
||||||
|
Zokeeper
|
||||||
|
ZTN
|
||||||
|
html
|
||||||
|
XXXXXXXXXXXXXXX
|
||||||
|
XXXXXXXXXXXXXXXXXXX
|
||||||
|
|
|
||||||
|
|
@ -0,0 +1,257 @@
|
||||||
|
---
|
||||||
|
id: probes
|
||||||
|
title: Declarative Approach to Chaos Hypothesis using Litmus Probes
|
||||||
|
sidebar_label: Probes
|
||||||
|
---
|
||||||
|
|
||||||
|
---
|
||||||
|
## Litmus Probes
|
||||||
|
|
||||||
|
Litmus probes are pluggable checks that can be defined within the ChaosEngine for any chaos experiment. The experiment pods execute these checks based on the mode they are defined in & factor their success as necessary conditions in determining the verdict of the experiment (along with the standard “in-built” checks).
|
||||||
|
|
||||||
|
Litmus currently supports four types of probes:
|
||||||
|
|
||||||
|
* **httpProbe:** To query health/downstream URIs
|
||||||
|
* **cmdProbe:** To execute any user-desired health-check function implemented as a shell command
|
||||||
|
* **k8sProbe:** To perform CRUD operations against native & custom Kubernetes resources
|
||||||
|
* **promProbe:** To execute promql queries and match prometheus metrics for specific criteria
|
||||||
|
|
||||||
|
These probes can be used in isolation or in several combinations to achieve the desired checks. While the `httpProbe` & `k8sProbe` are fully declarative in the way they are conceived, the `cmdProbe` expects the user to provide a shell command to implement checks that are highly specific to the application use case. `promProbe` expects the user to provide a promql query along with Prometheus service endpoints to check for specific criteria.
|
||||||
|
|
||||||
|
The probes can be set up to run in different modes:
|
||||||
|
|
||||||
|
* **SoT:** Executed at the Start of Test as a pre-chaos check
|
||||||
|
* **EoT:** Executed at the End of Test as a post-chaos check
|
||||||
|
* **Edge:** Executed both, before and after the chaos
|
||||||
|
* **Continuous:** The probe is executed continuously, with a specified polling interval during the chaos injection.
|
||||||
|
* **OnChaos:** The probe is executed continuously, with a specified polling interval strictly for chaos duration of chaos
|
||||||
|
|
||||||
|
All probes share some common attributes:
|
||||||
|
|
||||||
|
* **probeTimeout:** Represents the time limit for the probe to execute the check specified and return the expected data.
|
||||||
|
* **retry:** The number of times a check is re-run upon failure in the first attempt before declaring the probe status as failed.
|
||||||
|
* **interval:** The period between subsequent retries
|
||||||
|
* **probePollingInterval:** The time interval for which continuous probe should be sleep after each iteration
|
||||||
|
* **initialDelaySeconds:** Represents the initial waiting time interval for the probes.
|
||||||
|
|
||||||
|
## Types of Litmus Probes
|
||||||
|
|
||||||
|
### **httpProbe**
|
||||||
|
|
||||||
|
The `httpProbe` allows developers to specify a URL which the experiment uses to gauge health/service availability (or other custom conditions) as part of the entry/exit criteria. The received status code is mapped against an expected status. It supports http `Get` and `Post` methods.
|
||||||
|
|
||||||
|
In HTTP `Get` method it sends a http `GET` request to the provided url and matches the response code based on the given criteria(`==`, `!=`, `oneOf`).
|
||||||
|
|
||||||
|
In HTTP `Post` method it sends a http `POST` request to the provided url. The http body can be provided in the `body` field. In the case of a complex POST request in which the body spans multiple lines, the `bodyPath` attribute can be used to provide the path to a file consisting of the same. This file can be made available to the experiment pod via a ConfigMap resource, with the ConfigMap name being defined in the ChaosEngine OR the ChaosExperiment CR.
|
||||||
|
It can be defined at `.spec.experiments[].spec.probe` inside ChaosEngine.
|
||||||
|
|
||||||
|
> **NOTE:** `body` and `bodyPath` are mutually exclusive.
|
||||||
|
|
||||||
|
```yaml
|
||||||
|
probe:
|
||||||
|
- name: "check-frontend-access-url"
|
||||||
|
type: "httpProbe"
|
||||||
|
httpProbe/inputs:
|
||||||
|
url: "<url>"
|
||||||
|
insecureSkipVerify: false
|
||||||
|
method:
|
||||||
|
get:
|
||||||
|
criteria: == # supports == & != and oneof operations
|
||||||
|
responseCode: "<response code>"
|
||||||
|
mode: "Continuous"
|
||||||
|
runProperties:
|
||||||
|
probeTimeout: 5
|
||||||
|
interval: 5
|
||||||
|
retry: 1
|
||||||
|
probePollingInterval: 2
|
||||||
|
```
|
||||||
|
|
||||||
|
The `httpProbe` is better used in the Continuous mode of operation as a parallel liveness indicator of a target or downstream application. It uses the `probePollingInterval` property to specify the polling interval for the access checks.
|
||||||
|
|
||||||
|
> **NOTE:** `insecureSkipVerify` can be set to true to skip the certificate checks.
|
||||||
|
|
||||||
|
<br />
|
||||||
|
|
||||||
|
### **cmdProbe**
|
||||||
|
|
||||||
|
The `cmdProbe` allows developers to run shell commands and match the resulting output as part of the entry/exit criteria. The intent behind this probe was to allow users to implement a non-standard & imperative way for expressing their hypothesis. For example, the cmdProbe enables you to check for specific data within a database, parse the value out of a JSON blob being dumped into a certain path or check for the existence of a particular string in the service logs.
|
||||||
|
|
||||||
|
In order to enable this behaviour, the probe supports an inline mode in which the command is run from within the experiment image as well as a source mode, where the command execution is carried out from within a new pod whose image can be specified. While inline is preferred for simple shell commands , source mode can be used when application-specific binaries are required. The `cmdProbe` can be defined at `.spec.experiments[].spec.probe` the path inside the ChaosEngine.
|
||||||
|
|
||||||
|
```yaml
|
||||||
|
probe:
|
||||||
|
- name: "check-database-integrity"
|
||||||
|
type: "cmdProbe"
|
||||||
|
cmdProbe/inputs:
|
||||||
|
command: "<command>"
|
||||||
|
comparator:
|
||||||
|
type: "string" # supports: string, int, float
|
||||||
|
criteria: "contains" #supports >=,<=,>,<,==,!= for int and contains,equal,notEqual,matches,notMatches for string values
|
||||||
|
value: "<value-for-criteria-match>"
|
||||||
|
source: "<repo>/<tag>" # it can be “inline” or any image
|
||||||
|
mode: "Edge"
|
||||||
|
runProperties:
|
||||||
|
probeTimeout: 5
|
||||||
|
interval: 5
|
||||||
|
retry: 1
|
||||||
|
initialDelaySeconds: 5
|
||||||
|
```
|
||||||
|
|
||||||
|
<br />
|
||||||
|
|
||||||
|
### **k8sProbe**
|
||||||
|
|
||||||
|
With the proliferation of custom resources & operators, especially in the case of stateful applications, the steady-state is manifested as status parameters/flags within Kubernetes resources. k8sProbe addresses verification of the desired resource state by allowing users to define the Kubernetes GVR (group-version-resource) with appropriate filters (field selectors/label selectors). The experiment makes use of the Kubernetes Dynamic Client to achieve this. The `k8sProbe` can be defined at `.spec.experiments[].spec.probe` the path inside ChaosEngine.
|
||||||
|
|
||||||
|
It supports following CRUD operations which can be defined at `probe.operation`.
|
||||||
|
|
||||||
|
* **create:** It creates kubernetes resource based on the data provided inside probe.data field.
|
||||||
|
* **delete:** It deletes matching kubernetes resource via GVR and filters (field selectors/label selectors).
|
||||||
|
* **present:** It checks for the presence of kubernetes resource based on GVR and filters (field selectors/labelselectors).
|
||||||
|
* **absent:** It checks for the absence of kubernetes resource based on GVR and filters (field selectors/labelselectors).
|
||||||
|
|
||||||
|
```yaml
|
||||||
|
probe:
|
||||||
|
- name: "check-app-cluster-cr-status"
|
||||||
|
type: "k8sProbe"
|
||||||
|
k8sProbe/inputs:
|
||||||
|
command:
|
||||||
|
group: "<appGroup>"
|
||||||
|
version: "<appVersion>"
|
||||||
|
resource: "<appResource>"
|
||||||
|
namespace: "default"
|
||||||
|
fieldSelector: "metadata.name=<appResourceName>,status.phase=Running"
|
||||||
|
labelSelector: "<app-labels>"
|
||||||
|
operation: "present" # it can be present, absent, create, delete
|
||||||
|
mode: "EOT"
|
||||||
|
runProperties:
|
||||||
|
probeTimeout: 5
|
||||||
|
interval: 5
|
||||||
|
retry: 1
|
||||||
|
```
|
||||||
|
|
||||||
|
<br />
|
||||||
|
|
||||||
|
### **promProbe**
|
||||||
|
|
||||||
|
The `promProbe` allows users to run Prometheus queries and match the resulting output against specific conditions. The intent behind this probe is to allow users to define metrics-based SLOs in a declarative way and determine the experiment verdict based on its success. The probe runs the query on a Prometheus server defined by the `endpoint`, and checks whether the output satisfies the specified `criteria`.
|
||||||
|
|
||||||
|
The promql query can be provided in the `query` field. In the case of complex queries that span multiple lines, the `queryPath` attribute can be used to provide the link to a file consisting of the query. This file can be made available in the experiment pod via a ConfigMap resource, with the ConfigMap being passed in the ChaosEngine OR the ChaosExperiment CR.
|
||||||
|
|
||||||
|
> **NOTE:** `query` and `queryPath` are mutually exclusive.
|
||||||
|
|
||||||
|
```yaml
|
||||||
|
probe:
|
||||||
|
- name: "check-probe-success"
|
||||||
|
type: "promProbe"
|
||||||
|
promProbe/inputs:
|
||||||
|
endpoint: "<prometheus-endpoint>"
|
||||||
|
query: "<promql-query>"
|
||||||
|
comparator:
|
||||||
|
criteria: "==" #supports >=,<=,>,<,==,!= comparision
|
||||||
|
value: "<value-for-criteria-match>"
|
||||||
|
mode: "Edge"
|
||||||
|
runProperties:
|
||||||
|
probeTimeout: 5
|
||||||
|
interval: 5
|
||||||
|
retry: 1
|
||||||
|
```
|
||||||
|
|
||||||
|
<br />
|
||||||
|
|
||||||
|
---
|
||||||
|
|
||||||
|
## **Probe Status & Deriving Inferences**
|
||||||
|
|
||||||
|
The litmus chaos experiments run the probes defined in the ChaosEngine and update their stage-wise success in the ChaosResult custom resource, with details including the overall `probeSuccessPercentage` (a ratio of successful checks v/s total probes) and failure step, where applicable. The success of a probe is dependent on whether the expected status/results are met and also on whether it is successful in all the experiment phases defined by the probe’s execution mode. For example, probes that are executed in “Edge” mode, need the checks to be successful both during the pre-chaos & post-chaos phases to be declared as successful.
|
||||||
|
|
||||||
|
The pass criteria for an experiment is the logical conjunction of all probes defined in the ChaosEngine and an inbuilt entry/exit criteria. Failure of either indicates a failed hypothesis and is deemed experiment failure.
|
||||||
|
|
||||||
|
Provided below is a ChaosResult snippet containing the probe status for a mixed-probe ChaosEngine.
|
||||||
|
|
||||||
|
```yaml
|
||||||
|
Name: app-pod-delete
|
||||||
|
Namespace: test
|
||||||
|
Labels: name=app-pod-delete
|
||||||
|
Annotations: <none>
|
||||||
|
API Version: litmuschaos.io/v1alpha1
|
||||||
|
Kind: ChaosResult
|
||||||
|
Metadata:
|
||||||
|
Creation Timestamp: 2020-08-29T08:28:26Z
|
||||||
|
Generation: 36
|
||||||
|
Resource Version: 50239
|
||||||
|
Self Link: /apis/litmuschaos.io/v1alpha1/namespaces/test/ChaosResults/app-pod-delete
|
||||||
|
UID: b9e3638a-b7a4-4b93-bfea-bd143d91a5e8
|
||||||
|
Spec:
|
||||||
|
Engine: probe
|
||||||
|
Experiment: pod-delete
|
||||||
|
Status:
|
||||||
|
Experimentstatus:
|
||||||
|
Fail Step: N/A
|
||||||
|
Phase: Completed
|
||||||
|
Probe Success Percentage: 100
|
||||||
|
Verdict: Pass
|
||||||
|
|
||||||
|
Probe Status:
|
||||||
|
Name: check-frontend-access-url
|
||||||
|
Status:
|
||||||
|
Continuous: Passed 👍
|
||||||
|
Type: HTTPProbe
|
||||||
|
|
||||||
|
Name: check-app-cluster-cr-status
|
||||||
|
Status:
|
||||||
|
Post Chaos: Passed 👍 #EoT
|
||||||
|
Type: K8sProbe
|
||||||
|
|
||||||
|
Name: check-database-integrity
|
||||||
|
Status:
|
||||||
|
Post Chaos: Passed 👍 #Edge
|
||||||
|
Pre Chaos: Passed 👍
|
||||||
|
Type: CmdProbe
|
||||||
|
Events:
|
||||||
|
Type Reason Age From Message
|
||||||
|
---- ------ ---- ---- -------
|
||||||
|
Normal Summary 7s pod-delete-0s2jt6-s4rdx pod-delete experiment has been Passed
|
||||||
|
```
|
||||||
|
<br />
|
||||||
|
|
||||||
|
---
|
||||||
|
|
||||||
|
## **Probe Chaining**
|
||||||
|
|
||||||
|
Probe chaining enables reuse of probe a result (represented by the template function `{{ .<probeName>.probeArtifact.Register}})` in subsequent "downstream" probes defined in the ChaosEngine. Note that the order of execution of probes in the experiment depends purely on the order in which they are defined in the ChaosEngine.
|
||||||
|
|
||||||
|
Probe chaining is currently supported only for `cmdProbes`.
|
||||||
|
|
||||||
|
```yaml
|
||||||
|
probe:
|
||||||
|
- name: "probe1"
|
||||||
|
type: "cmdProbe"
|
||||||
|
cmdProbe/inputs:
|
||||||
|
command: "<command>"
|
||||||
|
comparator:
|
||||||
|
type: "string"
|
||||||
|
criteria: "equals"
|
||||||
|
value: "<value-for-criteria-match>"
|
||||||
|
source: "inline"
|
||||||
|
mode: "SOT"
|
||||||
|
runProperties:
|
||||||
|
probeTimeout: 5
|
||||||
|
interval: 5
|
||||||
|
retry: 1
|
||||||
|
- name: "probe2"
|
||||||
|
type: "cmdProbe"
|
||||||
|
cmdProbe/inputs:
|
||||||
|
## probe1's result being used as one of the args in probe2
|
||||||
|
command: "<commmand> {{ .probe1.ProbeArtifacts.Register }} <arg2>"
|
||||||
|
comparator:
|
||||||
|
type: "string"
|
||||||
|
criteria: "equals"
|
||||||
|
value: "<value-for-criteria-match>"
|
||||||
|
source: "inline"
|
||||||
|
mode: "SOT"
|
||||||
|
runProperties:
|
||||||
|
probeTimeout: 5
|
||||||
|
interval: 5
|
||||||
|
retry: 1
|
||||||
|
```
|
||||||
|
|
@ -31,7 +31,7 @@ module.exports = {
|
||||||
],
|
],
|
||||||
Concepts: [
|
Concepts: [
|
||||||
"workflow",
|
"workflow",
|
||||||
// "probes",
|
"probes",
|
||||||
// "cross-cloud-control",
|
// "cross-cloud-control",
|
||||||
// "litmusctl",
|
// "litmusctl",
|
||||||
// "crds",
|
// "crds",
|
||||||
|
|
|
||||||
Loading…
Reference in New Issue