We are trying out FusionAuth in clustered (more than 1 replica in Kubernetes). We are seeing this message a lot in the logs:
2023-08-17 06:29:20.688 PM ERROR io.fusionauth.api.service.cache.DistributedCacheNotifier - Failed to request a cache reload for [Applications, IdentityProvider, Keys] on [http://fusionauth.qa.svc.cluster.local:9011]. Status Code [-1]
Took [15015] ms
java.net.SocketTimeoutException: Read timed out
	at java.base/sun.nio.ch.NioSocketImpl.timedRead(NioSocketImpl.java:283)
	at java.base/sun.nio.ch.NioSocketImpl.implRead(NioSocketImpl.java:309)
	at java.base/sun.nio.ch.NioSocketImpl.read(NioSocketImpl.java:350)
	at java.base/sun.nio.ch.NioSocketImpl$1.read(NioSocketImpl.java:803)
	at java.base/java.net.Socket$SocketInputStream.read(Socket.java:966)
	at java.base/java.io.BufferedInputStream.fill(BufferedInputStream.java:244)
	at java.base/java.io.BufferedInputStream.read1(BufferedInputStream.java:284)
	at java.base/java.io.BufferedInputStream.read(BufferedInputStream.java:343)
	at java.base/sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:791)
	at java.base/sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:726)
	at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1688)
	at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1589)
	at java.base/java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:529)
	at com.inversoft.rest.RESTClient.go(RESTClient.java:403)
	at io.fusionauth.api.service.cache.DistributedCacheNotifier.callReload(DistributedCacheNotifier.java:201)
Our YAML file looks something like this:
apiVersion: apps/v1
kind: Deployment
metadata:
  name: fusionauth
  namespace: qa
spec:
  replicas: 1
  selector:
    matchLabels:
      app: fusionauth
  template:
    metadata:
      labels:
        app: fusionauth
    spec:
      containers:
        - name: fusionauth
          image: fusionauth/fusionauth-app:1.47.1
          ports:
            - containerPort: 9011
          env:
            - name: FUSIONAUTH_APP_MEMORY
              value: "2G"
            - name: FUSIONAUTH_APP_RUNTIME_MODE
              value: "production"
            - name: FUSIONAUTH_APP_URL
              value: "http://fusionauth.qa.svc.cluster.local:9011"
            - name: FUSIONAUTH_APP_USER_SEARCH_INDEX_NAME
              value: fusionauth-qa-user
            - name: FUSIONAUTH_APP_ENTITY_SEARCH_INDEX_NAME
              value: fusionauth-qa-entity
            - name: SEARCH_TYPE
              value: "elasticsearch"
            - name: PROXY_PORT
              value: "80"
            - name: DATABASE_CONNECTION_TIMEOUT
              value: "300000"
            - name: DATABASE_MAXIMUM_POOL_SIZE
              value: "20"
            - name: DATABASE_CONNECTION_HEALTHCHECK_99PERCENT_MS
              value: "1000"
            - name: FUSIONAUTH_SEARCH_ADDITIONAL_JAVA_ARGS
              value: "-Xms128m -Xmx2048m"
          resources:
            requests:
              cpu: "2000m"
              memory: "2.5Gi"
            limits:
              cpu: "4000m"
              memory: "3Gi"
---
apiVersion: v1
kind: Service
metadata:
  name: fusionauth
  namespace: qa
spec:
  type: ClusterIP
  ports:
    - port: 9011
  selector:
    app: fusionauth
I tested it by installing CURL in the FusionAuth image, it resolves the URL.