Merge pull request #253 from armab/fix/ssh-keygen-overwrite

Fix ssh_host key generation failure if file already exists

Author: coderanger

lib/kitchen/driver/docker.rb

@@ -217,8 +217,8 @@ def build_dockerfile
             ENV container docker
             RUN yum clean all
             RUN yum install -y sudo openssh-server openssh-clients which curl
-            RUN ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key -N ''
-            RUN ssh-keygen -t dsa -f /etc/ssh/ssh_host_dsa_key -N ''
+            RUN [ -f "/etc/ssh/ssh_host_rsa_key" ] || ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key -N ''
+            RUN [ -f "/etc/ssh/ssh_host_dsa_key" ] || ssh-keygen -t dsa -f /etc/ssh/ssh_host_dsa_key -N ''
           eos
         when 'arch'
           # See https://bugs.archlinux.org/task/47052 for why we
@@ -227,23 +227,23 @@ def build_dockerfile
             RUN pacman --noconfirm -Sy archlinux-keyring
             RUN pacman-db-upgrade
             RUN pacman --noconfirm -Sy openssl openssh sudo curl
-            RUN ssh-keygen -A -t rsa -f /etc/ssh/ssh_host_rsa_key
-            RUN ssh-keygen -A -t dsa -f /etc/ssh/ssh_host_dsa_key
+            RUN [ -f "/etc/ssh/ssh_host_rsa_key" ] || ssh-keygen -A -t rsa -f /etc/ssh/ssh_host_rsa_key
+            RUN [ -f "/etc/ssh/ssh_host_dsa_key" ] || ssh-keygen -A -t dsa -f /etc/ssh/ssh_host_dsa_key
             RUN echo >/etc/security/limits.conf
           eos
         when 'gentoo'
           <<-eos
             RUN emerge --sync
             RUN emerge net-misc/openssh app-admin/sudo
-            RUN ssh-keygen -A -t rsa -f /etc/ssh/ssh_host_rsa_key
-            RUN ssh-keygen -A -t dsa -f /etc/ssh/ssh_host_dsa_key
+            RUN [ -f "/etc/ssh/ssh_host_rsa_key" ] || ssh-keygen -A -t rsa -f /etc/ssh/ssh_host_rsa_key
+            RUN [ -f "/etc/ssh/ssh_host_dsa_key" ] || ssh-keygen -A -t dsa -f /etc/ssh/ssh_host_dsa_key
           eos
         when 'gentoo-paludis'
           <<-eos
             RUN cave sync
             RUN cave resolve -zx net-misc/openssh app-admin/sudo
-            RUN ssh-keygen -A -t rsa -f /etc/ssh/ssh_host_rsa_key
-            RUN ssh-keygen -A -t dsa -f /etc/ssh/ssh_host_dsa_key
+            RUN [ -f "/etc/ssh/ssh_host_rsa_key" ] || ssh-keygen -A -t rsa -f /etc/ssh/ssh_host_rsa_key
+            RUN [ -f "/etc/ssh/ssh_host_dsa_key" ] || ssh-keygen -A -t dsa -f /etc/ssh/ssh_host_dsa_key
           eos
         else
           raise ActionFailed,