How to create self signed certificate for Kubernetes Ingress controller

Create CA key

openssl genrsa -out ca.key 4096

Create CA certificate

openssl req -x509 -new -nodes -key ca.key -subj "/CN=*.example.com" -days 730 -out ca.crt

Create Certificate Key

openssl genrsa -out server.key 4096

Create a CSR file

Create a csr file with following content in "csr.conf"
vi csr.conf

[ req ]
default_bits = 4096
prompt = no
default_md = sha256
req_extensions = req_ext
distinguished_name = dn

[ dn ]
C = US
ST = New York
L = New York City
O = example
OU = IT
CN = *.example.com

[ req_ext ]
subjectAltName = @alt_names

[ alt_names ]
DNS.1 = kubernetes
DNS.2 = kubernetes.default
DNS.3 = kubernetes.default.svc
DNS.4 = kubernetes.default.svc.cluster
DNS.5 = kubernetes.default.svc.cluster.local
DNS.6 = dev.example.com


[ v3_ext ]
authorityKeyIdentifier=keyid,issuer:always
basicConstraints=CA:FALSE
keyUsage=keyEncipherment,dataEncipherment
extendedKeyUsage=serverAuth,clientAuth
subjectAltName=@alt_names

openssl req -new -key server.key -out server.csr -config csr.conf

Create a Certificate

openssl x509 -req -in server.csr -CA ca.crt -CAkey ca.key -CAcreateserial -out server.crt -days 730 -extensions v3_ext -extfile csr.conf

Test the Certificate

openssl x509  -noout -text -in ./server.crt