Configure Server Certificates

Couchbase Server Enterprise Edition supports X.509 certificates, for the encryption of communications between the server and networked clients.

Certificate-Management Preparation

Before configuring certificates for Couchbase Server, see the conceptual and architectural information provided in Certificates. Additionally, perform the following assessments:

Where should the configured CA, intermediate, and node keys reside? The procedure below generates all keys and certificates in a directory named SSLCA, which you can put anywhere on your filesystem.

The generated private node key (pkey.key) and chain certificate (chain.pem) must be posted in a specific place that is in the certificate trust path (such as /Users/<username>/Library/Application\ Support/Couchbase/var/lib/couchbase/inbox/ on MacOSX, or /opt/couchbase/var/lib/couchbase/inbox/) on Linux.
Does your cluster contain one node only, or multiple nodes? With one node, you will generate one node directory inside the directory SSLCA that will contain the private node key (pkey.key) and the certificate chain file (chain.pem). The node public key (pkey.pem) is included in the chain file.

With multiple nodes, you need to add an appropriate number of node directories with distinctive names, such as node-sales, node-hr, or whatever your situation requires.
Does your trust path contain a single intermediate CA, or multiple intermediate CAs? With only one CA, create one directory named int.

If you have multiple intermediate CAs, be sure to name them in a way that will allow you to stack them properly in the chain file, such as int1, int2, and so on. This order will show that the intermediate CA closest to the node (which signed the node certificate) has the higher number`.

Configure Server-Side Certificates

The following steps configure X.509 certificates for Couchbase Server on Ubuntu 16: a root certificate is created with a single intermediate certificate and a single node certificate; and a chain certificate is created from the intermediate and node certificates. The chain certificate and node private key are then made active for the current Couchbase Server-node.

Proceed as follows, using the sudo command where appropriate.

Create environment variables for the naming of a directory-structure, within which will reside the certificates you create for root, intermediate, and node.
```
export TOPDIR=SSLCA
export ROOT_DIR=rootdir
export NODE_DIR=nodedir
export INT_DIR=intdir
```
Note that in cases where multiple intermediate and/or node certificates are to be included in the certificate-chain, multiple intermediate and/or directories are required — one for each intermediate or node certificate.
Create environment variables for each of the certificate-files to be created.
```
export ROOT_CA=ca
export INTERMEDIATE=int
export NODE=pkey
export CHAIN=chain
```
Note that in cases where multiple intermediate and/or node certificates are to be included in the certificate-chain, additional environment-variable definitions — one for each of the additional intermediate and/or node certificates — are required.
Create environment variables for the administrator-credentials to be used for certificate management, the IP address at which the Couchbase Server-node is located, and the username required for role-based access to a particular resource.
```
export ADMINCRED=Administrator:password
export ip=10.143.173.101
export USERNAME=travel-sample
```
Note that in this example, the username is specified as travel-sample, which is typically associated with the Bucket Full Access role, on the bucket travel-sample. For access to be fully tested, ensure that the travel-sample user has indeed been defined on the Couchbase Server-node, and is associated with the Bucket Full Access role. (See Authorization for more information on RBAC.)
Create a directory-structure in which, within a top-level directory named SSLCA, three subdirectories reside — rootdir, intdir, and nodedir — respectively to hold the certificates you create for root, intermediate, and node.
```
mkdir ${TOPDIR}
cd ${TOPDIR}
mkdir ${ROOT_DIR}
mkdir ${INT_DIR}
mkdir ${NODE_DIR}
```

Generate the root private key file (ca.key) and the public key file (ca.pem):

cd ${ROOT_DIR}
openssl genrsa -out ${ROOT_CA}.key 2048
openssl req -new -x509 -days 3650 -sha256 -key ${ROOT_CA}.key \
-out ${ROOT_CA}.pem -subj '/C=UA/O=MyCompany/CN=MyCompanyRootCA'

Generate, first, the intermediate private key (int.key); and secondly, the intermediate certificate signing-request (int.csr):

cd ../${INT_DIR}
openssl genrsa -out ${INTERMEDIATE}.key 2048
openssl req -new -key ${INTERMEDIATE}.key -out ${INTERMEDIATE}.csr \
-subj '/C=UA/O=MyCompany/CN=MyCompanyIntermediateCA'

Create the extension-file v3_ca.ext; in order to add extensions to the certificate, and to generate the certificate signing-request:

cat <<EOF>> ./v3_ca.ext
subjectKeyIdentifier = hash
authorityKeyIdentifier = keyid:always,issuer:always
basicConstraints = CA:true
EOF

Generate the intermediate public key (int.pem), based on the intermediate certificate signing-request (int.csr), and signed by the root public key (ca.pem).

openssl x509 -req -in ${INTERMEDIATE}.csr \
-CA ../${ROOT_DIR}/${ROOT_CA}.pem -CAkey ../${ROOT_DIR}/${ROOT_CA}.key \
-CAcreateserial -CAserial ../${ROOT_DIR}/rootCA.srl -extfile ./v3_ca.ext \
-out ${INTERMEDIATE}.pem -days 365

Generate, first, the node private key (pkey.key); secondly, the node certificate signing-request (pkey.csr); and thirdly, the node public key (pkey.pem).

cd ../${NODE_DIR}
openssl genrsa -out ${NODE}.key 2048
openssl req -new -key ${NODE}.key -out ${NODE}.csr \
-subj "/C=UA/O=MyCompany/CN=${USERNAME}"
openssl x509 -req -in ${NODE}.csr -CA ../${INT_DIR}/${INTERMEDIATE}.pem \
-CAkey ../${INT_DIR}/${INTERMEDIATE}.key -CAcreateserial \
-CAserial ../${INT_DIR}/intermediateCA.srl -out ${NODE}.pem -days 365

Generate the certificate chain-file, by concatenating the node and intermediate certificates. This allows the client to verify the intermediate certificate against the root certificate.
```
cd ..
cat ./${NODE_DIR}/${NODE}.pem ./${INT_DIR}/${INTERMEDIATE}.pem > ${CHAIN}.pem
```
Note that if multiple intermediate certificates are specified for concatenation in this way, the concatenation-order must correspond to the order of signing. Thus, the node certificate, which appears in the first position, has been signed by the intermediate certificate, which therefore appears in the second position: and in cases where this intermediate certificate has itself been signed by a second intermediate certificate, the second intermediate certificate must appear in the third position, and so on.

Note also that the root certificate is never included in the chain.

Manually copy the node private key (pkey.key) and the chain file (chain.pem) to the inbox folder of the Couchbase Server-node:

mkdir /opt/couchbase/var/lib/couchbase/inbox/
cp ./${CHAIN}.pem /opt/couchbase/var/lib/couchbase/inbox/${CHAIN}.pem
chmod a+x /opt/couchbase/var/lib/couchbase/inbox/${CHAIN}.pem
cp ./${NODE_DIR}/${NODE}.key /opt/couchbase/var/lib/couchbase/inbox/${NODE}.key
chmod a+x /opt/couchbase/var/lib/couchbase/inbox/${NODE}.key

Upload the root certificate, and activate it:

curl -X POST --data-binary "@./${ROOT_DIR}/${ROOT_CA}.pem" \
http://${ADMINCRED}@${ip}:8091/controller/uploadClusterCA
curl -X POST http://${ADMINCRED}@${ip}:8091/node/controller/reloadCertificate

Note that alternatively, the following command-line interfaces can be used:

couchbase-cli ssl-manage -c ${ip}:8091 -u Administrator -p password \
--upload-cluster-ca=./${ROOT_DIR}/${ROOT_CA}.pem
couchbase-cli ssl-manage -c ${ip}:8091 -u Administrator -p password \
--set-node-certificate

For the current Couchbase Server-node, enable the client certificate:

curl -u ${ADMINCRED} -v -X POST http://${ip}:8091/settings/clientCertAuth \
-d '{"state": "enable","prefixes": [{"path": "subject.cn","prefix": "","delimiter": ""}]}'

For further information on certificate-deployment, see ssl-manage and Encryption On-the-Wire API.