openssl certificate signing request with SANs

example.com.cnf

[ req ]
default_bits       = 2048
distinguished_name = req_distinguished_name
req_extensions     = req_ext
attributes         = req_attributes
prompt             = no

[ req_distinguished_name ]
countryName                = US
stateOrProvinceName        = StateName
localityName               = CityName
emailAddress               = foo@example.com
organizationName           = Example Org
organizationalUnitName     = Example OU
commonName                 = example.com

[ req_attributes ]
challengePassword = put_a_password_here

[ req_ext ]
subjectAltName = @alt_names

[alt_names]
DNS.1   = foo.com
DNS.2   = bar.com

generate_csr.sh

openssl req -new -sha256 -newkey rsa:2048 -nodes -keyout example.com.key -out example.com.csr -config example.com.cnf