From 64f3702acde0a39ab2612b60b2e7b82cdba84a48 Mon Sep 17 00:00:00 2001
From: Ben Howard <ben.howard@redhat.com>
Date: Tue, 5 May 2020 10:35:37 -0600
Subject: [PATCH] templates: add
 etc-networkmanager-dispatcher.d-90-long-hostname.yaml

On GCP it is not uncommon to have DNS names that are too long.
Linux restricts the kernel hostname to being less than 63 characters.
The new template simply ensures that a hostname is set in the event that
NetworkManager is unable to do so.

Bug: 1809345
Signed-off-by: Ben Howard <ben.howard@redhat.com>
---
 ...manager-dispatcher.d-90-long-hostname.yaml | 40 +++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 templates/common/_base/files/etc-networkmanager-dispatcher.d-90-long-hostname.yaml

diff --git a/templates/common/_base/files/etc-networkmanager-dispatcher.d-90-long-hostname.yaml b/templates/common/_base/files/etc-networkmanager-dispatcher.d-90-long-hostname.yaml
new file mode 100644
index 0000000000..d65acf9923
--- /dev/null
+++ b/templates/common/_base/files/etc-networkmanager-dispatcher.d-90-long-hostname.yaml
@@ -0,0 +1,40 @@
+filesystem: "root"
+mode: 0755
+path: "/etc/NetworkManager/dispatcher.d/90-long-hostname"
+contents:
+  inline: |
+    #!/bin/bash
+    #
+    # On Google Compute Platform (GCP) the hostname may be too long (>63 chars).
+    # During firstboot the hostname is set in the initramfs before NetworkManager
+    # runs; on reboot affect nodes use 'localhost'. This hook is a simple work
+    # around: if the host name is longer than 63 characters, then the hostname
+    # is truncated at the _first_ dot.
+    #
+    # Additionally, this hook does not break DNS or cluster DNS resolution,
+    # since NetworkManager sets the appropriate /etc/resolv.conf settings.
+
+    IF=$1
+    STATUS=$2
+
+    log() { logger --tag "network-manager/$(basename $0)" "${@}"; }
+
+    # capture all eligible hostnames
+    if [[ ! "$(/bin/hostname)" =~ (localhost|localhost.local) ]]; then
+        log "hostname is already set"
+        exit 0
+    fi
+
+    if [[ ! "$STATUS" =~ (up|hostname|dhcp4-change|dhcp6-change) ]]; then
+        exit 0
+    fi
+
+    default_host="${DHCP4_HOST_NAME:-$DHCP6_HOST_NAME}"
+    # truncate the hostname to the first dot and than 64 characters.
+    host=$(echo ${default_host} | cut -f1 -d'.' | cut -c -63)
+
+    if [ "${#default_host}" -gt 63 ]; then
+        log "discovered hostname is longer than than 63 characters"
+        log "truncating ${default_host} => ${host}"
+        /bin/hostnamectl --transient set-hostname "${host}"
+    fi