Create and provision Proxmox LXC by pct command

proxmox_lxc_pct_provisioner.sh

pct create <id> /var/lib/vz/template/cache/centos-7-default_20170504_amd64.tar.xz \
    -arch amd64 \
    -ostype <centos|ubuntu|etc> \
    -hostname <hostname> \
    -cores <cores> \
    -memory <memory(MB)> \
    -swap <swap(MB)> \
    -storage local-lvm \
    -password \
    -net0 name=eth0,bridge=<bridge>,gw=<gateway>,ip=<cidr>,type=veth  &&\
pct start <id> &&\
sleep 10 &&\
pct resize <id> rootfs <storage(ex: +4G)> &&\
pct exec <id> -- bash -c "yum update -y &&\
    yum install -y openssh-server &&\
    systemctl start sshd &&\
    useradd -mU hogeuser &&\
    echo "password" | passwd --stdin hogeuser"
    

You can use a param -ssh-public-keys to push your keys during creating

# pct help create
...
  -ssh-public-keys <filepath>
             Setup public SSH keys (one key per line, OpenSSH format).
...