Reconcile Optimization¶
By default, an Argo CD Application is refreshed every time a resource that belongs to it changes.
Kubernetes controllers often update the resources they watch periodically, causing continuous reconcile operation on the Application
and a high CPU usage on the argocd-application-controller
. Argo CD allows you to optionally ignore resource updates on specific fields
for tracked resources.
For untracked resources, you can use the argocd.argoproj.io/ignore-resource-updates annotations
When a resource update is ignored, if the resource's health status does not change, the Application that this resource belongs to will not be reconciled.
System-Level Configuration¶
By default, resource.ignoreResourceUpdatesEnabled
is set to true
, enabling Argo CD to ignore resource updates. This default setting ensures that Argo CD maintains sustainable performance by reducing unnecessary reconcile operations. If you need to alter this behavior, you can explicitly set resource.ignoreResourceUpdatesEnabled
to false
in the argocd-cm
ConfigMap:
apiVersion: v1
kind: ConfigMap
metadata:
name: argocd-cm
namespace: argocd
data:
resource.ignoreResourceUpdatesEnabled: 'false'
Argo CD allows ignoring resource updates at a specific JSON path, using RFC6902 JSON patches and JQ path expressions. It can be configured for a specified group and kind
in resource.customizations
key of the argocd-cm
ConfigMap.
Following is an example of a customization which ignores the refreshTime
status field of an ExternalSecret
resource:
data:
resource.customizations.ignoreResourceUpdates.external-secrets.io_ExternalSecret:
|
jsonPointers:
- /status/refreshTime
# JQ equivalent of the above:
# jqPathExpressions:
# - .status.refreshTime
It is possible to configure ignoreResourceUpdates
to be applied to all tracked resources in every Application managed by an Argo CD instance. In order to do so, resource customizations can be configured like in the example below:
data:
resource.customizations.ignoreResourceUpdates.all: |
jsonPointers:
- /status
Using ignoreDifferences to ignore reconcile¶
By default, the existing system-level ignoreDifferences
customizations will be added to ignore resource updates as well. This helps reduce config management by preventing you to copy all existing ignore differences configurations.
To disable this behavior, the ignoreDifferencesOnResourceUpdates
setting can be disabled:
apiVersion: v1
kind: ConfigMap
metadata:
name: argocd-cm
data:
resource.compareoptions: |
ignoreDifferencesOnResourceUpdates: false
Default Configuration¶
By default, the metadata fields generation
, resourceVersion
and managedFields
are always ignored for all resources.
Finding Resources to Ignore¶
The application controller logs when a resource change triggers a refresh. You can use these logs to find high-churn resource kinds and then inspect those resources to find which fields to ignore.
To find these logs, search for "Requesting app refresh caused by object update"
. The logs include structured
fields for api-version
and kind
. Counting the number of refreshes triggered, by api-version/kind should
reveal the high-churn resource kinds.
Note
These logs are at the debug
level. Configure the application-controller's log level to debug
.
Once you have identified some resources which change often, you can try to determine which fields are changing. Here is one approach:
kubectl get <resource> -o yaml > /tmp/before.yaml
# Wait a minute or two.
kubectl get <resource> -o yaml > /tmp/after.yaml
diff /tmp/before.yaml /tmp/after
The diff can give you a sense for which fields are changing and should perhaps be ignored.
Checking Whether Resource Updates are Ignored¶
Whenever Argo CD skips a refresh due to an ignored resource update, the controller logs the following line: "Ignoring change of object because none of the watched resource fields have changed".
Search the application-controller logs for this line to confirm that your resource ignore rules are being applied.
Note
These logs are at the debug
level. Configure the application-controller's log level to debug
.
Examples¶
argoproj.io/Application¶
apiVersion: v1
kind: ConfigMap
metadata:
name: argocd-cm
data:
resource.customizations.ignoreResourceUpdates.argoproj.io_Application: |
jsonPointers:
# Ignore when ownerReferences change, for example when a parent ApplicationSet changes often.
- /metadata/ownerReferences
# Ignore reconciledAt, since by itself it doesn't indicate any important change.
- /status/reconciledAt
jqPathExpressions:
# Ignore lastTransitionTime for conditions; helpful when SharedResourceWarnings are being regularly updated but not
# actually changing in content.
- .status?.conditions[]?.lastTransitionTime
Ignoring updates for untracked resources¶
ArgoCD will only apply ignoreResourceUpdates
configuration to tracked resources of an application. This means dependant resources, such as a ReplicaSet
and Pod
created by a Deployment
, will not ignore any updates and trigger a reconcile of the application for any changes.
If you want to apply the ignoreResourceUpdates
configuration to an untracked resource, you can add the
argocd.argoproj.io/ignore-resource-updates=true
annotation in the dependent resources manifest.
Example¶
CronJob¶
apiVersion: batch/v1
kind: CronJob
metadata:
name: hello
namespace: test-cronjob
spec:
schedule: '* * * * *'
jobTemplate:
metadata:
annotations:
argocd.argoproj.io/ignore-resource-updates: 'true'
spec:
template:
metadata:
annotations:
argocd.argoproj.io/ignore-resource-updates: 'true'
spec:
containers:
- name: hello
image: busybox:1.28
imagePullPolicy: IfNotPresent
command:
- /bin/sh
- -c
- date; echo Hello from the Kubernetes cluster
restartPolicy: OnFailure
The resource updates will be ignored based on your the ignoreResourceUpdates
configuration in the argocd-cm
configMap:
argocd-cm
:
resource.customizations.ignoreResourceUpdates.batch_Job: |
jsonPointers:
- /status
resource.customizations.ignoreResourceUpdates.Pod: |
jsonPointers:
- /status