TLS certificates

This section only covers TLS certificates for the HTTP layer. TLS certificates for the transport layer that are used for internal communications between Elasticsearch nodes are managed by ECK and cannot be changed. You can however set your own certificate authority for the transport layer.

Default self-signed certificate

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By default, the operator manages a self-signed certificate with a custom CA for each resource. The CA, the certificate and the private key are each stored in a separate Secret.

> kubectl get secret | grep es-http
hulk-es-http-ca-internal         Opaque                                2      28m
hulk-es-http-certs-internal      Opaque                                2      28m
hulk-es-http-certs-public        Opaque                                1      28m

The public certificate is stored in a secret named <name>-[es|kb|apm|ent|agent]-http-certs-public.

> kubectl get secret hulk-es-http-certs-public -o go-template='{{index .data "tls.crt" | base64decode }}'
-----BEGIN CERTIFICATE-----
MIIDQDCCAiigAwIBAgIQHC4O/RWX15a3/P3upsm3djANBgkqhkiG9w0BAQsFADA6
...
QLYL4zLEby3vRxq65+xofVBJAaM=
-----END CERTIFICATE-----

Reserve static IP and custom domain

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To use a custom domain name with the self-signed certificate, you can reserve a static IP and/or use an Ingress instead of a LoadBalancer Service. Whatever you use, your DNS must be added to the certificate SAN in the spec.http.tls.selfSignedCertificate.subjectAltNames section of your Elastic resource manifest.

spec:
  http:
    service:
      spec:
        type: LoadBalancer
    tls:
      selfSignedCertificate:
        subjectAltNames:
        - ip: 160.46.176.15
        - dns: hulk.example.com

Setup your own certificate

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You can bring your own certificate to configure TLS to ensure that communication between HTTP clients and the Elastic Stack application is encrypted.

Create a Kubernetes secret with:

ca.crt: CA certificate (optional if tls.crt was issued by a well-known CA).
tls.crt: The certificate.
tls.key: The private key to the first certificate in the certificate chain.

If your tls.crt is signed by an intermediate CA you may need both the Root CA and the intermediate CA combined within the ca.crt file depending on whether the Root CA is globally trusted.

kubectl create secret generic my-cert --from-file=ca.crt --from-file=tls.crt --from-file=tls.key

Alternatively you can also bring your own CA certificate including a private key and let ECK issue certificates with it. Any certificate SANs you have configured as decribed in Reserve static IP and custom domain will also be respected when issuing certificates with this CA certificate.

Create a Kubernetes secret with:

ca.crt: CA certificate.
ca.key: The private key to the CA certificate.

kubectl create secret generic my-cert --from-file=ca.crt --from-file=ca.key

In both cases, you have to reference the secret name in the http.tls.certificate section of the resource manifest.

spec:
  http:
    tls:
      certificate:
        secretName: my-cert

Disable TLS

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You can explicitly disable TLS for Kibana, APM Server, Enterprise Search and the HTTP layer of Elasticsearch.

spec:
  http:
    tls:
      selfSignedCertificate:
        disabled: true

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