Configuring Your SSL Certificate for Proper HTTPS

A default installation of the Looker application uses self-signed SSL certificates for HTTPS. For production environments, we recommend installing an SSL certificate from a trusted vendor.

To use an SSL certificate with Looker, you will need to create a Java keystore with your certificate and key.

We assume you have the following files:

Install the Certificate

These files should all exist in the same directory. The default is /home/looker/looker/.ssl.

  1. Create the new directory and make it the current directory:

    mkdir /home/looker/looker/.ssl
    cd /home/looker/looker/.ssl
  2. Choose a password for the keystore and put it in a file called .keystorepass:

    echo "some_password_here" > .keystorepass
  3. If you have a CA file, append it to the end of your certificate file:

    echo >> looker.pem
    cat ca.pem >> looker.pem
  4. Convert the certificate and key to a pkcs12 keystore:

    openssl pkcs12 -export \
      -in looker.pem       \
      -inkey looker.key    \
      -out importme.p12
  5. You will be prompted for an export password. Use the one you put in the .keystorepass file above.

  6. Convert the pkcs12 keystore to a Java keystore:

    keytool -importkeystore     \
      -srckeystore importme.p12 \
      -destkeystore looker.jks  \
      -srcstoretype pkcs12      \
      -alias 1
  7. You will be prompted for the new keystore password and the pkcs12 keystore password. Keep using the one in the .keystorepass file.

  8. Now you are ready to start Looker with the new keystore. Your new Looker startup command should look like:

    java <your java options here>                        \
      -jar looker.jar start                              \
      --ssl-keystore=/home/looker/looker/.ssl/looker.jks \

Validate the Certificate

Once Looker is running, you can verify that your cert is correctly installed with OpenSSL s_client.

openssl s_client -connect localhost:9999

If your hostname is, you should see a line in the output like this:

subject=/OU=Domain Control Validated/

Another way to check is with wget. This test can be performed from any host which has network access to your Looker instance via HTTPS.

On a Looker using the default self-signed certificate, the output shows the certificate common name

$ wget
--2014-12-31 12:06:03--
Resolving (
Connecting to (||:9999... connected.
ERROR: cannot verify's certificate, issued by ‘/’:
  Self-signed certificate encountered.
    ERROR: certificate common name ‘’ doesn't match requested host name ‘’.
To connect to insecurely, use `--no-check-certificate'.

On a Looker using a certificate from a certificate authority, the certificate common name must match the DNS name that clients use to access Looker (or an equivalent wildcard certificate).

Here is an example of a server using a “real” (non-self signed) certificate:

$ wget
--2014-12-31 12:06:47--
Resolving (
Connecting to (||:9999... connected.
HTTP request sent, awaiting response... 302 Found
Location: [following]
--2014-12-31 12:06:48--
Connecting to (||:9999... connected.
HTTP request sent, awaiting response... 200 OK
Length: 3491 (3.4K) [text/html]
Saving to: ‘index.html’

100%[====================================================>] 3,491       --.-K/s   in 0.07s

2014-12-31 12:06:48 (50.5 KB/s) - ‘index.html’ saved [3491/3491]

Disabling Insecure SSL Protocols

If you need to remove insecure TLS for security compliance, add this line to your $JAVA_HOME/lib/security/ file:

jdk.tls.disabledAlgorithms= SSLv2Hello, SSLv3, TLSv1, TLSv1.1

Next Step

After you have setup your SSL certificate you’re ready to add port forwarding for a cleaner URL.