Hostname verification failure

Versions (relevant - OpenSearch):
Opensearch 2.9.0
Opensearch security plugin

Describe the issue:
Hi, I am trying to use the security plugin in opensearch installed thorugh helm using the demo certificates. While I’m working on that, I enabled the hostname_verification as true. When I see the logs, it tells that javax.net.ssl.SSLHandshakeException: No subject alternative DNS name matching opensearch-cluster-master-headless found. And also when I tried to hit the curl https://localhost:9200 -u admin:admin — insecure it shows opensearch security not initialised.

Configuration:
plugins:
security:
ssl:
transport:
pemcert_filepath: esnode.pem
pemkey_filepath: esnode-key.pem
pemtrustedcas_filepath: root-ca.pem
enforce_hostname_verification: true
http:
enabled: true
pemcert_filepath: esnode.pem
pemkey_filepath: esnode-key.pem
pemtrustedcas_filepath: root-ca.pem
allow_unsafe_democertificates: true
allow_default_init_securityindex: true
authcz:
admin_dn:
- CN=kirk,OU=client,O=client,L=test,C=de
audit.type: internal_opensearch
enable_snapshot_restore_privilege: true
check_snapshot_restore_write_privileges: true
restapi:
roles_enabled: [“all_access”, “security_rest_api_access”]
system_indices:
enabled: true
indices:
[
“.opendistro-alerting-config”,
“.opendistro-alerting-alert*”,
“.opendistro-anomaly-results*”,
“.opendistro-anomaly-detector*”,
“.opendistro-anomaly-checkpoints”,
“.opendistro-anomaly-detection-state”,
“.opendistro-reports-",
".opendistro-notifications-
”,
“.opendistro-notebooks”,
“.opendistro-asynchronous-search-response*”,
]

Relevant Logs or Screenshots:

@Sugilal Could you share the full values.yml file? Please redact all sensitive data.
Please paste it as the preformatted text.

image

---
clusterName: "opensearch-cluster"
nodeGroup: "master"

# If discovery.type in the opensearch configuration is set to "single-node",
# this should be set to "true"
# If "true", replicas will be forced to 1
singleNode: false

# The service that non master groups will try to connect to when joining the cluster
# This should be set to clusterName + "-" + nodeGroup for your master group
masterService: "opensearch-cluster-master"

# OpenSearch roles that will be applied to this nodeGroup
# These will be set as environment variable "node.roles". E.g. node.roles=master,ingest,data,remote_cluster_client
roles:
  - master
  - ingest
  - data
  - remote_cluster_client

replicas: 3

# if not set, falls back to parsing .Values.imageTag, then .Chart.appVersion.
majorVersion: ""

global:
  # Set if you want to change the default docker registry, e.g. a private one.
  dockerRegistry: ""

# Allows you to add any config files in {{ .Values.opensearchHome }}/config
opensearchHome: /usr/share/opensearch
# such as opensearch.yml and log4j2.properties
config:
  # Values must be YAML literal style scalar / YAML multiline string.
  # <filename>: |
  #   <formatted-value(s)>
  # log4j2.properties: |
  #   status = error
  #
  #   appender.console.type = Console
  #   appender.console.name = console
  #   appender.console.layout.type = PatternLayout
  #   appender.console.layout.pattern = [%d{ISO8601}][%-5p][%-25c{1.}] [%node_name]%marker %m%n
  #
  #   rootLogger.level = info
  #   rootLogger.appenderRef.console.ref = console
  opensearch.yml: |
    cluster.name: opensearch-cluster

    # Bind to all interfaces because we don't know what IP address Docker will assign to us.
    network.host: 0.0.0.0

    # Setting network.host to a non-loopback address enables the annoying bootstrap checks. "Single-node" mode disables them again.
    # Implicitly done if ".singleNode" is set to "true".
    # discovery.type: single-node

    # Start OpenSearch Security Demo Configuration
    # WARNING: revise all the lines below before you go into production
    plugins:
      security:
        ssl:
          transport:
            pemcert_filepath: esnode.pem
            pemkey_filepath: esnode-key.pem
            pemtrustedcas_filepath: root-ca.pem
            enforce_hostname_verification: true
          http:
            enabled: true
            pemcert_filepath: esnode.pem
            pemkey_filepath: esnode-key.pem
            pemtrustedcas_filepath: root-ca.pem
        allow_unsafe_democertificates: true
        allow_default_init_securityindex: true
        authcz:
          admin_dn:
            - CN=kirk,OU=client,O=client,L=test,C=de
        audit.type: internal_opensearch
        enable_snapshot_restore_privilege: true
        check_snapshot_restore_write_privileges: true
        restapi:
          roles_enabled: ["all_access", "security_rest_api_access"]
        system_indices:
          enabled: true
          indices:
            [
              ".opendistro-alerting-config",
              ".opendistro-alerting-alert*",
              ".opendistro-anomaly-results*",
              ".opendistro-anomaly-detector*",
              ".opendistro-anomaly-checkpoints",
              ".opendistro-anomaly-detection-state",
              ".opendistro-reports-*",
              ".opendistro-notifications-*",
              ".opendistro-notebooks",
              ".opendistro-asynchronous-search-response*",
            ]
    ######## End OpenSearch Security Demo Configuration ########
  # log4j2.properties:

# Extra environment variables to append to this nodeGroup
# This will be appended to the current 'env:' key. You can use any of the kubernetes env
# syntax here
extraEnvs: []
#  - name: MY_ENVIRONMENT_VAR
#    value: the_value_goes_here

# Allows you to load environment variables from kubernetes secret or config map
envFrom: []
# - secretRef:
#     name: env-secret
# - configMapRef:
#     name: config-map

# A list of secrets and their paths to mount inside the pod
# This is useful for mounting certificates for security and for mounting
# the X-Pack license
secretMounts: []

hostAliases: []
# - ip: "127.0.0.1"
#   hostnames:
#   - "foo.local"
#   - "bar.local"

image:
  repository: "opensearchproject/opensearch"
  # override image tag, which is .Chart.AppVersion by default
  tag: ""
  pullPolicy: "IfNotPresent"

podAnnotations: {}
  # iam.amazonaws.com/role: es-cluster

# OpenSearch Statefulset annotations
openSearchAnnotations: {}

# additionals labels
labels: {}

opensearchJavaOpts: "-Xmx512M -Xms512M"

resources:
  requests:
    cpu: "1000m"
    memory: "100Mi"

initResources: {}
#  limits:
#     cpu: "25m"
#     memory: "128Mi"
#  requests:
#     cpu: "25m"
#     memory: "128Mi"

sidecarResources: {}
#   limits:
#     cpu: "25m"
#     memory: "128Mi"
#   requests:
#     cpu: "25m"
#     memory: "128Mi"

networkHost: "0.0.0.0"

rbac:
  create: false
  serviceAccountAnnotations: {}
  serviceAccountName: ""
  # Controls whether or not the Service Account token is automatically mounted to /var/run/secrets/kubernetes.io/serviceaccount
  automountServiceAccountToken: false

podSecurityPolicy:
  create: false
  name: ""
  spec:
    privileged: true
    fsGroup:
      rule: RunAsAny
    runAsUser:
      rule: RunAsAny
    seLinux:
      rule: RunAsAny
    supplementalGroups:
      rule: RunAsAny
    volumes:
      - secret
      - configMap
      - persistentVolumeClaim
      - emptyDir

persistence:
  enabled: true
  # Set to false to disable the `fsgroup-volume` initContainer that will update permissions on the persistent disk.
  enableInitChown: true
  # override image, which is busybox by default
  # image: busybox
  # override image tag, which is latest by default
  # imageTag:
  labels:
    # Add default labels for the volumeClaimTemplate of the StatefulSet
    enabled: false
  # OpenSearch Persistent Volume Storage Class
  # If defined, storageClassName: <storageClass>
  # If set to "-", storageClassName: "", which disables dynamic provisioning
  # If undefined (the default) or set to null, no storageClassName spec is
  #   set, choosing the default provisioner.  (gp2 on AWS, standard on
  #   GKE, AWS & OpenStack)
  #
  # storageClass: "-"
  accessModes:
    - ReadWriteOnce
  size: 8Gi
  annotations: {}

extraVolumes: []
  # - name: extras
  #   emptyDir: {}

extraVolumeMounts: []
  # - name: extras
  #   mountPath: /usr/share/extras
  #   readOnly: true

extraContainers: []
  # - name: do-something
  #   image: busybox
  #   command: ['do', 'something']

extraInitContainers: []
  # - name: do-somethings
  #   image: busybox
  #   command: ['do', 'something']

# This is the PriorityClass settings as defined in
# https://kubernetes.io/docs/concepts/configuration/pod-priority-preemption/#priorityclass
priorityClassName: ""

# By default this will make sure two pods don't end up on the same node
# Changing this to a region would allow you to spread pods across regions
antiAffinityTopologyKey: "kubernetes.io/hostname"

# Hard means that by default pods will only be scheduled if there are enough nodes for them
# and that they will never end up on the same node. Setting this to soft will do this "best effort"
antiAffinity: "soft"

# This is the node affinity settings as defined in
# https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#node-affinity-beta-feature
nodeAffinity: {}

# This is the pod topology spread constraints
# https://kubernetes.io/docs/concepts/workloads/pods/pod-topology-spread-constraints/
topologySpreadConstraints: []

# The default is to deploy all pods serially. By setting this to parallel all pods are started at
# the same time when bootstrapping the cluster
podManagementPolicy: "Parallel"

# The environment variables injected by service links are not used, but can lead to slow OpenSearch boot times when
# there are many services in the current namespace.
# If you experience slow pod startups you probably want to set this to `false`.
enableServiceLinks: true

protocol: https
httpPort: 9200
transportPort: 9300
metricsPort: 9600
httpHostPort: ""
transportHostPort: ""


service:
  labels: {}
  labelsHeadless: {}
  headless:
    annotations: {}
  type: ClusterIP
  # The IP family and IP families options are to set the behaviour in a dual-stack environment
  # Omitting these values will let the service fall back to whatever the CNI dictates the defaults
  # should be
  #
  # ipFamilyPolicy: SingleStack
  # ipFamilies:
  # - IPv4
  nodePort: ""
  annotations: {}
  httpPortName: http
  transportPortName: transport
  metricsPortName: metrics
  loadBalancerIP: ""
  loadBalancerSourceRanges: []
  externalTrafficPolicy: ""

updateStrategy: RollingUpdate

# This is the max unavailable setting for the pod disruption budget
# The default value of 1 will make sure that kubernetes won't allow more than 1
# of your pods to be unavailable during maintenance
maxUnavailable: 1

podSecurityContext:
  fsGroup: 1000
  runAsUser: 1000

securityContext:
  capabilities:
    drop:
      - ALL
  # readOnlyRootFilesystem: true
  runAsNonRoot: true
  runAsUser: 1000

securityConfig:
  enabled: true
  path: "/usr/share/opensearch/config/opensearch-security"
  actionGroupsSecret:
  configSecret:
  internalUsersSecret:
  rolesSecret:
  rolesMappingSecret:
  tenantsSecret:
  # The following option simplifies securityConfig by using a single secret and
  # specifying the config files as keys in the secret instead of creating
  # different secrets for for each config file.
  # Note that this is an alternative to the individual secret configuration
  # above and shouldn't be used if the above secrets are used.
  config:
    # There are multiple ways to define the configuration here:
    # * If you define anything under data, the chart will automatically create
    #   a secret and mount it. This is best option to choose if you want to override all the
    #   existing yml files at once.
    # * If you define securityConfigSecret, the chart will assume this secret is
    #   created externally and mount it. This is best option to choose if your intention is to
    #   only update a single yml file.
    # * It is an error to define both data and securityConfigSecret.
    securityConfigSecret: ""
    dataComplete: true
    data: {}
      # config.yml: |-
      # internal_users.yml: |-
      # roles.yml: |-
      # roles_mapping.yml: |-
      # action_groups.yml: |-
      # tenants.yml: |-

# How long to wait for opensearch to stop gracefully
terminationGracePeriod: 120

sysctlVmMaxMapCount: 262144

startupProbe:
  tcpSocket:
    port: 9200
  initialDelaySeconds: 5
  periodSeconds: 10
  timeoutSeconds: 3
  failureThreshold: 30

livenessProbe: {}
  # periodSeconds: 20
  # timeoutSeconds: 5
  # failureThreshold: 10
  # successThreshold: 1
  # initialDelaySeconds: 10
  # tcpSocket:
  #   port: 9200

readinessProbe:
  tcpSocket:
    port: 9200
  periodSeconds: 5
  timeoutSeconds: 3
  failureThreshold: 3

## Use an alternate scheduler.
## ref: https://kubernetes.io/docs/tasks/administer-cluster/configure-multiple-schedulers/
##
schedulerName: ""

imagePullSecrets: []
nodeSelector: {}
tolerations: []

# Enabling this will publically expose your OpenSearch instance.
# Only enable this if you have security enabled on your cluster
ingress:
  enabled: false
  # For Kubernetes >= 1.18 you should specify the ingress-controller via the field ingressClassName
  # See https://kubernetes.io/blog/2020/04/02/improvements-to-the-ingress-api-in-kubernetes-1.18/#specifying-the-class-of-an-ingress
  # ingressClassName: nginx

  annotations: {}
    # kubernetes.io/ingress.class: nginx
    # kubernetes.io/tls-acme: "true"
  path: /
  hosts:
    - chart-example.local
  tls: []
  #  - secretName: chart-example-tls
  #    hosts:
  #      - chart-example.local

nameOverride: ""
fullnameOverride: ""

masterTerminationFix: false

opensearchLifecycle: {}
  # preStop:
  #   exec:
  #     command: ["/bin/sh", "-c", "echo Hello from the preStart handler > /usr/share/message"]
  # postStart:
  #   exec:
  #     command: ["/bin/sh", "-c", "echo Hello from the postStart handler > /usr/share/message"]

lifecycle: {}
  # preStop:
  #   exec:
  #     command: ["/bin/sh", "-c", "echo Hello from the postStart handler > /usr/share/message"]
  # postStart:
  #   exec:
  #     command:
  #       - bash
  #       - -c
  #       - |
  #         #!/bin/bash
  #         # Add a template to adjust number of shards/replicas1
  #         TEMPLATE_NAME=my_template
  #         INDEX_PATTERN="logstash-*"
  #         SHARD_COUNT=8
  #         REPLICA_COUNT=1
  #         ES_URL=http://localhost:9200
  #         while [[ "$(curl -s -o /dev/null -w '%{http_code}\n' $ES_URL)" != "200" ]]; do sleep 1; done
  #         curl -XPUT "$ES_URL/_template/$TEMPLATE_NAME" -H 'Content-Type: application/json' -d'{"index_patterns":['\""$INDEX_PATTERN"\"'],"settings":{"number_of_shards":'$SHARD_COUNT',"number_of_replicas":'$REPLICA_COUNT'}}'

keystore: []
# To add secrets to the keystore:
#  - secretName: opensearch-encryption-key

networkPolicy:
  create: false
  ## Enable creation of NetworkPolicy resources. Only Ingress traffic is filtered for now.
  ## In order for a Pod to access OpenSearch, it needs to have the following label:
  ## {{ template "uname" . }}-client: "true"
  ## Example for default configuration to access HTTP port:
  ## opensearch-master-http-client: "true"
  ## Example for default configuration to access transport port:
  ## opensearch-master-transport-client: "true"

  http:
    enabled: true

# Deprecated
# please use the above podSecurityContext.fsGroup instead
fsGroup: ""

## Set optimal sysctl's through securityContext. This requires privilege. Can be disabled if
## the system has already been preconfigured. (Ex: https://www.elastic.co/guide/en/elasticsearch/reference/current/vm-max-map-count.html)
## Also see: https://kubernetes.io/docs/tasks/administer-cluster/sysctl-cluster/
sysctl:
  enabled: false

## Set optimal sysctl's through privileged initContainer.
sysctlInit:
  enabled: false
  # override image, which is busybox by default
  # image: busybox
  # override image tag, which is latest by default
  # imageTag:

## Enable to add 3rd Party / Custom plugins not offered in the default OpenSearch image.
plugins:
  enabled: true
  installList: []
  # - example-fake-plugin

# -- Array of extra K8s manifests to deploy
extraObjects: []
  # - apiVersion: secrets-store.csi.x-k8s.io/v1
  #   kind: SecretProviderClass
  #   metadata:
  #     name: argocd-secrets-store
  #   spec:
  #     provider: aws
  #     parameters:
  #       objects: |
  #         - objectName: "argocd"
  #           objectType: "secretsmanager"
  #           jmesPath:
  #               - path: "client_id"
  #                 objectAlias: "client_id"
  #               - path: "client_secret"
  #                 objectAlias: "client_secret"
  #     secretObjects:
  #     - data:
  #       - key: client_id
  #         objectName: client_id
  #       - key: client_secret
  #         objectName: client_secret
  #       secretName: argocd-secrets-store
  #       type: Opaque
  #       labels:
  #         app.kubernetes.io/part-of: argocd
  # - |
  #    apiVersion: policy/v1
  #    kind: PodDisruptionBudget
  #    metadata:
  #      name: {{ template "opensearch.uname" . }}
  #      labels:
  #        {{- include "opensearch.labels" . | nindent 4 }}
  #    spec:
  #      minAvailable: 1
  #      selector:
  #        matchLabels:
  #          {{- include "opensearch.selectorLabels" . | nindent 6 }}

I used only the default settings .

This is the name of the Kubernetes service that OpenSearch nodes are using to communicate.
This is defined in the statefulset.yml file in opensearch/templates.

If you take a look into the OpenSearch pods environment, you’ll find that OpenSearch has discovery.seed_hosts set to opensearch-cluster-master-headless which is also defined in the statefulset.yml.

I think the best workaround is to configure custom certificates with opensearch-cluster-master-headless DNS name in the SAN.

When I tried with custom certificates, I am getting no subject alternative names matching Ip address found error.

@Sugilal Could you share outputs of the below commands?

kubectl get svc
kubectl get pod -o wide

@pablo Actually, I don’t know how to use the custom certificates in the helm installed OpenSearch. So, I tried installing the OpenSearch in tar and use those certificates. The configuration I used is mentioned below.

cluster.name: opensearch
node.name: node2
network.host: 0.0.0.0
node.roles: [ data, ingest, master, remote_cluster_client ]
http.port: 9202
discovery.seed_hosts: ["localhost"]
cluster.initial_master_nodes: ["node1", "node2"]

# Transport
plugins.security.ssl.transport.pemcert_filepath: transport.pem
plugins.security.ssl.transport.pemkey_filepath: transportkey.pem
plugins.security.ssl.transport.pemtrustedcas_filepath: rootCA.pem

plugins.security.ssl.transport.enforce_hostname_verification: true
plugins.security.ssl.transport.resolve_hostname: false

# Create default security index '.opendistro_security'
plugins.security.allow_default_init_securityindex: true

# Node DN
plugins.security.nodes_dn:
  - 'CN=transport'

plugins.security.restapi.roles_enabled: ["all_access", "security_rest_api_access"]

@Sugilal Does the IP address error relate to Helm Charts or tar deployment?

@pablo This was run on tar deployment only. I created the custom certificates and ran on tar deployment, and it tells this IP address error.

@Sugilal In that case the error is referring to your IP address of the host. Demo certificates don’t have that IP in SAN or CN. If you’d like to use a hostname verification, you must create a certificate that contains that information either in SAN or CN.

Could you share the full error?

@pablo This is the full error message. And we can’t expose the IP in certificates. Is there any workaround other than mentioning ip in certificates?

[2023-09-07T12:36:10,670][INFO ][o.o.s.c.ConfigurationRepository] [node2] Node started, try to initialize it. Wait for at least yellow cluster state....
[2023-09-07T12:36:10,757][ERROR][o.o.s.s.t.SecuritySSLNettyTransport] [node2] Exception during establishing a SSL connection: javax.net.ssl.SSLHandshakeException: No subject alternative names matching IP address 192.168.191.46 found
javax.net.ssl.SSLHandshakeException: No subject alternative names matching IP address 192.168.191.46 found
        at sun.security.ssl.Alert.createSSLException(Alert.java:131) ~[?:?]
        at sun.security.ssl.TransportContext.fatal(TransportContext.java:369) ~[?:?]
        at sun.security.ssl.TransportContext.fatal(TransportContext.java:312) ~[?:?]
        at sun.security.ssl.TransportContext.fatal(TransportContext.java:307) ~[?:?]
        at sun.security.ssl.CertificateMessage$T13CertificateConsumer.checkServerCerts(CertificateMessage.java:1357) ~[?:?]
        at sun.security.ssl.CertificateMessage$T13CertificateConsumer.onConsumeCertificate(CertificateMessage.java:1232) ~[?:?]
        at sun.security.ssl.CertificateMessage$T13CertificateConsumer.consume(CertificateMessage.java:1175) ~[?:?]
        at sun.security.ssl.SSLHandshake.consume(SSLHandshake.java:396) ~[?:?]
        at sun.security.ssl.HandshakeContext.dispatch(HandshakeContext.java:480) ~[?:?]
        at sun.security.ssl.SSLEngineImpl$DelegatedTask$DelegatedAction.run(SSLEngineImpl.java:1267) ~[?:?]
        at sun.security.ssl.SSLEngineImpl$DelegatedTask$DelegatedAction.run(SSLEngineImpl.java:1254) ~[?:?]
        at java.security.AccessController.doPrivileged(AccessController.java:691) ~[?:?]
        at sun.security.ssl.SSLEngineImpl$DelegatedTask.run(SSLEngineImpl.java:1199) ~[?:?]
        at io.netty.handler.ssl.SslHandler.runDelegatedTasks(SslHandler.java:1547) ~[netty-handler-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:1393) ~[netty-handler-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.handler.ssl.SslHandler.decodeJdkCompatible(SslHandler.java:1234) ~[netty-handler-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.handler.ssl.SslHandler.decode(SslHandler.java:1283) ~[netty-handler-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:507) ~[netty-codec-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:446) ~[netty-codec-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:276) ~[netty-codec-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) [netty-transport-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) [netty-transport-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) [netty-transport-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) [netty-transport-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) [netty-transport-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) [netty-transport-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919) [netty-transport-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166) [netty-transport-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:722) [netty-transport-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeysPlain(NioEventLoop.java:623) [netty-transport-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:586) [netty-transport-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:496) [netty-transport-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:986) [netty-common-4.1.72.Final.jar:4.1.72.Final]
        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) [netty-common-4.1.72.Final.jar:4.1.72.Final]
        at java.lang.Thread.run(Thread.java:832) [?:?]
Caused by: java.security.cert.CertificateException: No subject alternative names matching IP address 192.168.191.46 found
        at sun.security.util.HostnameChecker.matchIP(HostnameChecker.java:165) ~[?:?]
        at sun.security.util.HostnameChecker.match(HostnameChecker.java:101) ~[?:?]
        at sun.security.ssl.X509TrustManagerImpl.checkIdentity(X509TrustManagerImpl.java:452) ~[?:?]
        at sun.security.ssl.X509TrustManagerImpl.checkIdentity(X509TrustManagerImpl.java:426) ~[?:?]
        at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:292) ~[?:?]
        at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:144) ~[?:?]
        at sun.security.ssl.CertificateMessage$T13CertificateConsumer.checkServerCerts(CertificateMessage.java:1335) ~[?:?]
        ... 30 more

Any update on this?

@Sugilal I’ve tested the helm charts with a custom certificate and opensearch-cluster-master-headless in CN and SAN. I’ve got the same results.

Once the transport layer traffic passed the opensearch-cluster-master-headless service, the error changed to the IP of the pod.

I’m still testing it.

Any update on this?

@Sugilal I did further testing but couldn’t get it to work. Once the OpenSearch passes the service and communicates with the pod, it starts using an IP address instead of FQDN.

@pablo thanks for the analysis, Can I raise this issue as a bug in opensearch?

@Sugilal Please do and share the link to the bug here.

@pablo Hostname verification failure · Issue #3997 · opensearch-project/security (github.com)
here is the link for the bug raised.