let
  pkgs = import <nixpkgs> {};

  runWithOpenSSL = file: cmd: pkgs.runCommand file {
    buildInputs = [ pkgs.openssl_1_1_0 ];
  } ("export RANDFILE=/tmp/rnd;" + cmd);

  etcd_cnf = pkgs.writeText "etcd-openssl.cnf" ''
    [req]
    req_extensions = v3_req
    distinguished_name = req_distinguished_name
    [req_distinguished_name]
    [ v3_req ]
    basicConstraints = CA:FALSE
    keyUsage = digitalSignature, keyEncipherment
    extendedKeyUsage = serverAuth
    subjectAltName = @alt_names
    [alt_names]
    DNS.1 = etcd0
    DNS.2 = etcd1
    DNS.3 = etcd2
    DNS.4 = k8s0-0
    DNS.5 = k8s0-1
    DNS.6 = k8s0-2
    IP.1 = 127.0.0.1
  '';

  etcd_client_cnf = pkgs.writeText "etcd-client-openssl.cnf" ''
    [req]
    req_extensions = v3_req
    distinguished_name = req_distinguished_name
    [req_distinguished_name]
    [ v3_req ]
    basicConstraints = CA:FALSE
    keyUsage = digitalSignature, keyEncipherment
    extendedKeyUsage = clientAuth
  '';

  apiserver_cnf = pkgs.writeText "apiserver-openssl.cnf" ''
    [req]
    req_extensions = v3_req
    distinguished_name = req_distinguished_name
    [req_distinguished_name]
    [ v3_req ]
    basicConstraints = CA:FALSE
    keyUsage = nonRepudiation, digitalSignature, keyEncipherment
    subjectAltName = @alt_names
    [alt_names]
    DNS.1 = kubernetes
    DNS.2 = kubernetes.default
    DNS.3 = kubernetes.default.svc
    DNS.4 = kubernetes.default.svc.cluster.local
    DNS.4 = k8s0-0.itpartner.no
    IP.1 = 10.0.0.1
    IP.2 = 10.253.18.100
  '';

  worker_cnf = pkgs.writeText "worker-openssl.cnf" ''
    [req]
    req_extensions = v3_req
    distinguished_name = req_distinguished_name
    [req_distinguished_name]
    [ v3_req ]
    basicConstraints = CA:FALSE
    keyUsage = nonRepudiation, digitalSignature, keyEncipherment
    subjectAltName = @alt_names
    [alt_names]
    DNS.1 = *.itpartner.no
    DNS.2 = *.itpartner.intern
    DNS.3 = k8s0-0
    DNS.4 = k8s0-1
    DNS.5 = k8s0-2
    DNS.6 = git01
  '';

  ca_key = runWithOpenSSL "ca-key.pem" "openssl genrsa -out $out 2048";
  ca_pem = runWithOpenSSL "ca.pem" ''
    openssl req \
      -x509 -new -nodes -key ${ca_key} \
      -days 10000 -out $out -subj "/CN=kube-ca"
  '';

  etcd_key = runWithOpenSSL "etcd-key.pem" "openssl genrsa -out $out 2048";
  etcd_csr = runWithOpenSSL "etcd.csr" ''
    openssl req \
      -new -key ${etcd_key} \
      -out $out -subj "/CN=etcd" \
      -config ${etcd_cnf}
  '';
  etcd_cert = runWithOpenSSL "etcd.pem" ''
    openssl x509 \
      -req -in ${etcd_csr} \
      -CA ${ca_pem} -CAkey ${ca_key} \
      -CAcreateserial -out $out \
      -days 365 -extensions v3_req \
      -extfile ${etcd_cnf}
  '';

  etcd_client_key = runWithOpenSSL "etcd-client-key.pem"
    "openssl genrsa -out $out 2048";
  etcd_client_csr = runWithOpenSSL "etcd-client.csr" ''
    openssl req \
      -new -key ${etcd_client_key} \
      -out $out -subj "/CN=etcd-client" \
      -config ${etcd_client_cnf}
  '';
  etcd_client_cert = runWithOpenSSL "etcd-client.pem" ''
    openssl x509 \
      -req -in ${etcd_client_csr} \
      -CA ${ca_pem} -CAkey ${ca_key} -CAcreateserial \
      -out $out -days 365 -extensions v3_req \
      -extfile ${etcd_client_cnf}
  '';

  apiserver_key = runWithOpenSSL "apiserver-key.pem"
    "openssl genrsa -out $out 2048";
  apiserver_csr = runWithOpenSSL "apiserver.csr" ''
    openssl req \
      -new -key ${apiserver_key} \
      -out $out -subj "/CN=kube-apiserver" \
      -config ${apiserver_cnf}
  '';
  apiserver_cert = runWithOpenSSL "apiserver.pem" ''
    openssl x509 \
      -req -in ${apiserver_csr} \
      -CA ${ca_pem} -CAkey ${ca_key} -CAcreateserial \
      -out $out -days 365 -extensions v3_req \
      -extfile ${apiserver_cnf}
  '';

  worker_key = runWithOpenSSL "worker-key.pem" "openssl genrsa -out $out 2048";
  worker_csr = runWithOpenSSL "worker.csr" ''
    openssl req \
      -new -key ${worker_key} \
      -out $out -subj "/CN=kube-worker" \
      -config ${worker_cnf}
  '';
  worker_cert = runWithOpenSSL "worker.pem" ''
    openssl x509 \
      -req -in ${worker_csr} \
      -CA ${ca_pem} -CAkey ${ca_key} -CAcreateserial \
      -out $out -days 365 -extensions v3_req \
      -extfile ${worker_cnf}
  '';
in
{
  inherit ca_key ca_pem;
  inherit etcd_key etcd_cert;
  inherit etcd_client_key etcd_client_cert;
  inherit apiserver_key apiserver_cert;
  inherit worker_key worker_cert;
}