Set hostname explicitly in cloud-init for proxy nodes

we've seen the nodename gets overwritten to an appended hash; hence setting it in the user_data.txt
172.20.10.32
ssh-proxy

172.20.10.6
http-proxy-edbc74b

172.20.10.20
ood-2101a36

.gitlab-ci.yml

@@ -225,6 +225,7 @@ deploy_http_proxy_node:
     - |
       cat > user_data.txt <<EOF
       #!/bin/bash
+      hostnamectl set-hostname ${HTTP_PROXY_INSTANCE_NAME} --static
       cat >> /etc/NetworkManager/conf.d/90-dns-none.conf<<EEOF
       [main]
       dns=none
@@ -278,6 +279,7 @@ deploy_ssh_proxy_node:
     - |
       cat > user_data.txt <<EOF
       #!/bin/bash
+      hostnamectl set-hostname ${SSH_PROXY_INSTANCE_NAME} --static
       cat >> /etc/NetworkManager/conf.d/90-dns-none.conf<<EEOF
       [main]
       dns=none