start installation with ssh-copy-id, allow custom kexec tarball

nixos-remote

@@ -46,6 +46,9 @@ while [[ $# -gt 0 ]]; do
       kexec_url=$2
       shift
       ;;
+    --no-ssh-copy-id)
+      no_ssh_copy=y
+      ;;
     *)
       if [ -z ${ssh_connection+x} ]; then
         ssh_connection=$1
@@ -95,15 +98,19 @@ else
   abort "flake must be set"
 fi
 
+
 # wait for machine to become reachable (possibly forever)
-until ssh_ -o ConnectTimeout=10 -- exit 0; do sleep 5; done
+if [ ${no_ssh_copy-n} != "y" ]; then
+  until ssh-copy-id "$ssh_connection"; do sleep 5; done
+else
+  until ssh_ -o ConnectTimeout=10 -- exit 0; do sleep 5; done
+fi
 
 # first check if the remote system is kexec booted
 if $(ssh_ -- test -e /etc/is_kexec); then
   is_kexec=y
 fi
 
-echo ${is_kexec-n}
 if [ ${is_kexec-n} != "y" ]; then
   # TODO we probably need an architecture detection here
   ssh_ << SSH
@@ -113,6 +120,19 @@ if [[ "\$os" != "Linux" ]]; then
   echo "This script requires Linux as the operating system, but got \${os}" >&2
   exit 1
 fi
+if ! command -v tar >/dev/null 2>&1; then
+  echo "no tar command found, but required to unpack kexec tarball" >&2
+  exit 1
+fi
+
+rm -rf /root/kexec
+mkdir -p /root/kexec
+SSH
+
+if [[ -e "$kexec_url" ]]; then
+  cat "$kexec_url" | ssh_ 'tar -C /root/kexec -xvzf-'
+else
+  ssh_ << SSH
 fetch(){
   if command -v curl >/dev/null 2>&1; then
     curl --fail -Ss -L "\$1"
@@ -123,17 +143,15 @@ fetch(){
     exit 1
   fi
 }
-if ! command -v tar >/dev/null 2>&1; then
-  echo "no tar command found, but required to unpack kexec tarball" >&2
-  exit 1
+fetch "$kexec_url" | tar -C /root/kexec -xvzf-
+SSH
 fi
 
-rm -rf /root/kexec
-mkdir -p /root/kexec
-fetch "$kexec_url" | tar -C /root/kexec -xvzf-
+ssh_ << SSH
 export TMPDIR=/root/kexec
 setsid /root/kexec/kexec/run
 SSH
+
   # wait for machine to become unreachable
   while timeout_ssh_ -- exit 0; do sleep 1; done