fist commit - images lib in a working condition for debian

lib/images/commons/scripts-n-files.nix

@@ -0,0 +1,59 @@
+# minimal set of scripts and services by various images
+{ pkgs, lib, ... }: {
+  # bring back simple interface names like eth0 eth1 etc
+  grub-ifnames-0 = pkgs.writeText "grub-ifnames-0" ''
+    GRUB_CMDLINE_LINUX="net.ifnames=0 biosdevname=0 $GRUB_CMDLINE_LINUX"
+  '';
+
+  # no need for CPU microcode updating in VMs
+  grub-disable-microcode = pkgs.writeText "grub-disable-microcode" ''
+    GRUB_CMDLINE_LINUX="dis_ucode_ldr $GRUB_CMDLINE_LINUX"
+  '';
+
+  # dhcp for eth0
+  eth0-dhcp-network = pkgs.writeText "eth0-network" ''
+    [Match]
+    Name=eth0
+
+    [Network]
+    DHCP=yes
+  '';
+
+  # generate ssh host keys before starting sshd
+  ssh-service-override-conf-create = pkgs.writeScript "ssh-override-conf-create.sh" ''
+    mkdir -p /etc/systemd/system/ssh.service.d
+
+    cat > /etc/systemd/system/ssh.service.d/override.conf << EOF
+    [Service]
+    ExecStartPre=
+    ExecStartPre=`which ssh-keygen` -A
+    ExecStartPre=`which sshd` -t
+
+    EOF
+  '';
+
+  # script to grow root partition
+  grow-root-sh = pkgs.writeScript "grow-root-sh" ''
+    #!/bin/bash
+    set -e
+
+    command -v growpart >/dev/null || { >&2 echo "growpart not found. Install package cloud-guest-utils or cloud-utils."; exit 1; }
+
+    ROOTPART=$(findmnt / -o source -n)
+    DISK=''${ROOTPART%[0-9]*}
+    PARTNUM=''${ROOTPART##*[!0-9]}
+
+    # resize and grow if possible
+    growpart "$DISK" "$PARTNUM" && resize2fs "$ROOTPART" || true
+  '';
+
+  # service to grow root partition on boot
+  grow-root-service = pkgs.writeText "grow-root-service" ''
+    [Service]
+    Type = oneshot
+    ExecStart = /usr/local/sbin/grow-root.sh
+
+    [Install]
+    WantedBy = multi-user.target
+  '';
+}