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.
You should have the following files:
- A certificate file named
looker.pemthat contains your primary certificate
- An associated key file named
- Optionally, an intermediate Certificate Authority (CA) chain file named
.pemfile does not need to contain a root certificate.
Install the certificate
These files should all exist in the same directory. The default is
Create the new directory and make it the current directory:
mkdir /home/looker/looker/.ssl cd /home/looker/looker/.ssl
Choose a password for the keystore and put it in a file called
echo "some_password_here" > .keystorepass
If you have a CA file, append it to the end of your certificate file:
echo >> looker.pem cat ca.pem >> looker.pem
Convert the certificate and key to a
openssl pkcs12 -export \ -in looker.pem \ -inkey looker.key \ -out importme.p12
You will be prompted for an export password. Use the one you put in the
Convert the pkcs12 keystore to a Java keystore:
keytool -importkeystore \ -srckeystore importme.p12 \ -destkeystore looker.jks \ -srcstoretype pkcs12 \ -alias 1
You will be prompted for the new keystore password and the pkcs12 keystore password. Keep using the one in the
Create a file named
lookerstart.cfgin the same directory as your
looker.jar. This file will configure the requisite Looker options every time Looker starts. The file should contain:
Validate the certificate
Once Looker is running, you can verify that your cert is correctly installed with OpenSSL
openssl s_client -connect localhost:9999
If your hostname is
looker.yourdomain.com, you should see a line in the output like this:
subject=/OU=Domain Control Validated/CN=looker.yourdomain.com
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 https://looker.yourdomain.com:9999 --2014-12-31 12:06:03-- https://looker.yourdomain.com:9999/ Resolving looker.yourdomain.com (looker.yourdomain.com)... 192.168.23.66 Connecting to looker.yourdomain.com (looker.yourdomain.com)|192.168.23.66|:9999... connected. ERROR: cannot verify looker.yourdomain.com's certificate, issued by ‘/CN=self-signed.looker.com’: Self-signed certificate encountered. ERROR: certificate common name ‘self-signed.looker.com’ doesn't match requested host name ‘looker.yourdomain.com’. To connect to looker.yourdomain.com 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 https://looker.yourdomain.com:9999 --2014-12-31 12:06:47-- https://looker.yourdomain.com:9999/ Resolving looker.yourdomain.com (looker.yourdomain.com)... 10.10.10.10 Connecting to looker.yourdomain.com (looker.yourdomain.com)|10.10.10.10|:9999... connected. HTTP request sent, awaiting response... 302 Found Location: https://looker.yourdomain.com:9999/login [following] --2014-12-31 12:06:48-- https://looker.yourdomain.com:9999/login Connecting to looker.yourdomain.com (looker.yourdomain.com)|10.10.10.10|: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]
Validating a site’s certificate against the CA bundle
As of Looker 5.18, Looker uses the Java Certificate Authority (CA) root certificate bundle. Looker uses the CA bundle to verify the authenticity of the hosts with which it communicates when making outbound requests from the Looker server. This includes actions like making requests to outbound webhooks, performing S3 backups, requesting various forms of authentication, and communicating with the license-verification server.
Java provides and manages the CA bundle, which resides on disk. This allows the admins of customer-hosted Looker instances to add or remove certificates from the CA bundle.
If you choose to modify the CA bundle, you can use Looker’s
test_ssl_cert_validation utility to test whether or not Looker can validate a server certificate when making an outbound HTTP connection. The utility accepts the name of a file that contains a list of URLs you want to test, with one URL per line, like this:
https://www.google.com https://looker.com https://wrong.host.badssl.com/
If the name of this file was
hosts, you would use
test_ssl_cert_validation like this:
$ ./looker test_ssl_cert_validation hosts
The output of
test_ssl_cert_validation would look like this:
Using CA file from .../jre/lib/security/cacerts Attempting connection to https://www.google.com Certificate verified successfully, connection returned with: HTTP/1.1 200 OK Attempting connection to https://looker.com Certificate verified successfully, connection returned with: HTTP/1.1 200 OK Attempting connection to https://wrong.host.badssl.com/ Error connecting to https://wrong.host.badssl.com/: OpenSSL::SSL::SSLError: hostname "wrong.host.badssl.com" does not match the server certificate Summary: Successes: 3, Redirects: 0, Failures: 1
Disabling insecure SSL protocols
If you need to remove insecure TLS for security compliance, add this line to your
jdk.tls.disabledAlgorithms=SSLv2Hello, SSLv3, TLSv1, TLSv1.1, 3DES_EDE_CBC
After you have set up your SSL certificate, you will be ready to add port forwarding for a cleaner URL.