As I am highly dependent on official documentation, I found that Apache Solr maintain an awesome documentation from which I learned a lot. Setting up SSL can be found here. I am writing this for easier step by step setup.

Happy Searching!

Generate certificate & key

From the official documentation, you can generate a self-signed certificate to test your setup. But for the trusted authority, generate a certificate and convert it to .pfx format, which is type PKCS12.

And before starting Solr, we need to configure zookeeper.

Configure Zookeeper

We must configure Solr cluster properties in Zookeeper so that Solr nodes know to communicate via SSL. After creating, setting up and starting Zookeeper, we need to setup urlScheme cluster-wide property to https before any Solr nodes start up.

For Unix, go to $solr_home and run,

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server/scripts/cloud-scripts/zkcli.sh -zkhost server1:2181,server2:2181,server3:2181 -cmd clusterprop -name urlScheme -val https

For existing collections, we can update cluster properties by using the Collections API (CLUSTERPROP):

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http://IP:8983/solr/admin/collections?action=CLUSTERPROP&name=urlScheme&val=https

This command only needs to be run on one node of the cluster, the change will apply to all nodes.

From SolrCloud documentation, you’ll find a way to setup SSL which is self-signed certificate. For production, we needed to setup SSL certificate from an authorized CA. You will have to buy Mulit-Domain SSL (SAN certificate) to cover SolrCloud setup. I’m going to share my experience on how did I setup SSL on our SolrCloud.

Our SolrCloud was consisted of 3 servers. Suppose, they are:

  1. 192.0.0.1
  2. 192.0.0.2
  3. 192.0.0.3

By accessing http://192.0.0.1:8983, we can access to Solr frontend. For three servers, there are three frontend. We have to secure

Configure Solr

At this point, I think we all have set up zookeeper properly, have certificates and key at hand and didn’t start Solr. Now, let’s set up system properties of Solr in $solr_home/bin/solr.in.sh or, /etc/default/solr.in.sh:

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SOLR_SSL_ENABLED=true
SOLR_SSL_KEY_STORE=/etc/solr-ssl.keystore.p12    # define your store path
SOLR_SSL_KEY_STORE_PASSWORD=secret    # use your store password
SOLR_SSL_TRUST_STORE=/etc/solr-ssl.keystore.p12    # define your store path
SOLR_SSL_TRUST_STORE_PASSWORD=secret    # use your store password
SOLR_SSL_NEED_CLIENT_AUTH=false
SOLR_SSL_WANT_CLIENT_AUTH=false
SOLR_SSL_CHECK_PEER_NAME=true

Now, start Solr and it’s working.

If you use curl, see the official documentation section on how to use curl in case of SSL.