Install On-Premise Nexus Sonatype Artefact repository [ SSL Enabled ]

 1.  Download the Nexus Open source from Nexus Sonatype website

https://help.sonatype.com/repomanager3/download/download-archives---repository-manager-3

2. Unzip it and place the file into /opt/nexus folder

3. To create Nexus service to start and stop add nexus.service file with the following content

[Unit]
Description=nexus service
After=network.target
  
[Service]
Type=forking
LimitNOFILE=65536
ExecStart=/opt/nexus/nexus-3.34.0-01/bin/nexus start
ExecStop=/opt/nexus/nexus-3.34.0-01/bin/nexus stop
User=tamilarasan
Restart=on-abort
TimeoutSec=600
  
[Install]
WantedBy=multi-user.target

4. Copy the file into /etc/systemd/system/ folder & enable the service

$ sudo cp nexus.service /etc/systemd/system

$ sudo systemctl daemon-reload

$ sudo systemctl enable nexus.service

$ sudo systemctl start nexus.service

5. Verify the Nexus status 

$sudo systemctl status nexus.service

6. To check the nexus log file 

7. Setup the initial admin password

By default the initial password will be stored into ' admin.password' file into $data-dir

8. Create Self -Signed certificate to enable Nexus with https

# 1 Generate public private key pair using keytool:

keytool -genkeypair -keystore keystore.jks -storepass password -alias tamilcloud.com \

 -keyalg RSA -keysize 2048 -validity 5000 -keypass password \

 -dname 'CN=*.tamilcloud.com, OU=Sonatype, O=Sonatype, L=Unspecified, ST=Unspecified, C=US' \

 -ext 'SAN=DNS:nexus.tamilcloud.com,DNS:clm.tamilcloud.com,DNS:repo.tamilcloud.com,DNS:www.tamilcloud.com'

 # 2. Generate PEM encoded public certificate file using keytool:

keytool -exportcert -keystore keystore.jks -alias tamilcloud.com -rfc > tamilcloud.cert

# 3. Convert our Java specific keystore binary".jks" file to a widely compatible PKCS12 keystore ".p12" file:

keytool -importkeystore -srckeystore keystore.jks -destkeystore tamilcloud.p12 -deststoretype PKCS12

# 4. Extract pem (certificate) from ".p12" keystore file ( this is same as step 2, but openssl spits out more verbose contents ):

openssl pkcs12 -nokeys -in tamilcloud.p12 -out tamilcloud.pem

# 5. Extract unencrypted private key file from ".p12" keystore file:

openssl pkcs12 -nocerts -nodes -in tamilcloud.p12 -out tamilcloud.key

# 6. List and verify new keystore file contents:

keytool -list -keystore tamilcloud.p12 -storetype PKCS12

# 7. copy tamilcloud.cert to the same folder as ca.crt root certificate

mv tamilcloud.cert ca.crt

# 8. Add host name in to /etc/hosts file

1*.*.*.*      www.tamilcloud.com repo.tamilcloud.com clm.tamilcloud.com nexus.tamilcloud.com

9. Copy Java keystore file at $data-dir/etc/ssl/keystore.jks

$ mkdir -p /opt/nexus/sonatype-work/nexus3/etc/ssl

cp keystore.jks /opt/nexus/sonatype-work/nexus3/etc/ssl/

10. Edit $data-dir/etc/nexus-default.properties and save the file after making the following changes. Add a new line containing:

application-port-ssl=8443

10. update the nexus-arg int the nexus-default.properties file

nexus-args=${jetty.etc}/jetty.xml,${jetty.etc}/jetty-http.xml,${jetty.etc}/jetty-https.xml,${jetty.etc}/jetty-requestlog.xml

11. Update the application host value as specific ip address

application-host=1*.*.*.*

12.  Run the Nexus and start Use it :)

Reference: 

1. SSL Configuration :  https://help.sonatype.com/repomanager3/system-configuration/configuring-ssl#ConfiguringSSL-ServingSSLDirectly

2. Prepare Self sign certificate : https://support.sonatype.com/hc/en-us/articles/213465768-SSL-Certificate-Guide?_ga=2.104409540.550049495.1630897268-1578994290.1629198342

3. Configure Runtime environment : https://help.sonatype.com/repomanager3/installation/configuring-the-runtime-environment