Hi,
creating selfsigned certificate with openssl is one step 
This command creates a 4096 Bit key ( myKey.key ) and the corresponding selfsigned public key (myCert.pem).
1 2 3 4 5 6 7 8 9 | michael@debdev ~ # openssl req -x509 \-newkey rsa:4096 \-keyout myKey.key \-out myCert.pem \-sha256 \-days 365 \-batch \-nodes \-subj "/C=DE/ST=Franken/L=Nuremburg/O=my Organizaton/OU=My Department/CN=myHostname.myDomain.org/emailAddress=myEMailAddress@myDomain.org" |
and with keyusage and extented key usage
1 | openssl req -x509 -newkey rsa:2048 -keyout private.key -out cert.pem -days 365 -nodes -subj "/CN=myServer.myDomain.org" -addext "keyUsage=keyEncipherment,dataEncipherment" -addext "extendedKeyUsage=serverAuth" |
If you don’t want to set a passphrase on the private key omit the -nodes switch.
Michael