Regenerate knox gateway SSL certificate annually (#326)

Needed for Dataproc component gateway

Author: june-hua

startupscript/dataproc/startup.sh

@@ -762,6 +762,145 @@ if [[ -f ~/.ssh-agent/environment ]]; then
 fi
 EOF
 
+###################################
+# Setup Knox certificate auto-renewal
+###################################
+# Knox Gateway SSL certificates expire. Setup annual renewal
+# to prevent Component Gateway web interfaces from becoming inactive.
+
+emit "Setting up Knox Gateway certificate auto-renewal..."
+
+readonly KNOX_REGEN_SCRIPT="/usr/local/bin/regenerate-knox-cert.sh"
+readonly KNOX_CRON_FILE="/etc/cron.d/knox-cert-regeneration"
+
+# Create the regeneration script
+cat << 'KNOX_REGEN_EOF' > "${KNOX_REGEN_SCRIPT}"
+#!/bin/bash
+#
+# Name: regenerate-knox-cert.sh
+#
+# Description:
+#   Script to regenerate the Knox Gateway SSL certificate on a Dataproc cluster.
+#
+# Reference:
+#   https://docs.cloud.google.com/dataproc/docs/concepts/accessing/dataproc-gateways#regenerate
+#
+
+set -o errexit
+set -o nounset
+set -o pipefail
+set -o xtrace
+
+# Knox keystore configuration
+readonly KNOX_KEYSTORE="/var/lib/knox/security/keystores/gateway.jks"
+readonly BACKUP_DIR="/var/lib/knox/security/keystores/backup"
+readonly BACKUP_TIMESTAMP=$(date +%Y%m%d_%H%M%S)
+readonly BACKUP_FILE="${BACKUP_DIR}/gateway_${BACKUP_TIMESTAMP}.jks"
+
+#######################################
+# Emit a message with a timestamp
+# Logs are captured by systemd journal when run via cron
+#######################################
+function emit() {
+  echo "$(date '+%Y-%m-%d %H:%M:%S') $*"
+}
+readonly -f emit
+
+emit "Starting Knox Gateway SSL certificate regeneration check..."
+
+# Only run on the dataproc master node. Exit with error if otherwise.
+ROLE="$(/usr/share/google/get_metadata_value attributes/dataproc-role)"
+if [[ "${ROLE}" != 'Master' ]]; then
+  emit "ERROR: This script must be run on the Dataproc master node. Current role: ${ROLE}"
+  exit 1
+fi
+readonly ROLE
+
+emit "Running on Dataproc master node."
+
+# Check if keystore exists
+if [[ ! -f "${KNOX_KEYSTORE}" ]]; then
+  emit "ERROR: Knox keystore not found at ${KNOX_KEYSTORE}"
+  exit 1
+fi
+
+# Check certificate year before proceeding
+emit "Checking certificate year..."
+CERT_INFO=$(echo "" | keytool -list -v -keystore "${KNOX_KEYSTORE}" 2>&1)
+
+# Extract the certificate creation date and year
+CERT_CREATION_DATE=$(echo "${CERT_INFO}" | grep -i "Creation date:" | head -n 1 | sed 's/.*Creation date: //')
+
+if [[ -z "${CERT_CREATION_DATE}" ]]; then
+  emit "WARNING: Could not extract certificate creation date. Proceeding with regeneration."
+else
+  # Extract year from certificate date (last token)
+  CERT_YEAR=$(echo "${CERT_CREATION_DATE}" | awk '{print $NF}')
+  CURRENT_YEAR=$(date +%Y)
+
+  emit "Certificate creation date: ${CERT_CREATION_DATE}"
+  emit "Certificate year: ${CERT_YEAR}"
+  emit "Current year: ${CURRENT_YEAR}"
+
+  # Only regenerate if certificate is from a previous year
+  if [[ "${CERT_YEAR}" == "${CURRENT_YEAR}" ]]; then
+    emit "Certificate was created this year (${CURRENT_YEAR}). Skipping regeneration."
+    exit 0
+  fi
+
+  emit "Certificate is from year ${CERT_YEAR}. Proceeding with regeneration..."
+fi
+
+# Create backup directory if it doesn't exist
+mkdir -p "${BACKUP_DIR}"
+
+# Backup the current keystore
+emit "Backing up current keystore to ${BACKUP_FILE}"
+cp "${KNOX_KEYSTORE}" "${BACKUP_FILE}"
+
+if [[ ! -f "${BACKUP_FILE}" ]]; then
+  emit "ERROR: Failed to create backup of keystore"
+  exit 1
+fi
+
+emit "Backup created successfully."
+
+# Remove the old keystore to trigger regeneration
+emit "Removing old keystore..."
+rm -f "${KNOX_KEYSTORE}"
+
+# Restart Knox service to generate new certificate
+emit "Restarting Knox service to generate new certificate..."
+systemctl restart knox
+
+emit "Knox Gateway SSL certificate regeneration completed successfully."
+
+exit 0
+KNOX_REGEN_EOF
+
+chmod +x "${KNOX_REGEN_SCRIPT}"
+
+# Create cron job
+# Use systemd-cat to send output to journalctl with identifier 'knox-cert-regen'
+cat << EOF > "${KNOX_CRON_FILE}"
+# Knox Gateway SSL Certificate Regeneration
+# Checks certificate year and regenerates if from previous year
+# Logs are sent to journalctl and can be viewed with: journalctl -t knox-cert-regen
+
+# Check annually at 2 AM on January 1st (ensures cert is regenerated yearly)
+0 2 1 1 * root systemd-cat -t knox-cert-regen ${KNOX_REGEN_SCRIPT}
+
+# Also check on reboot (regenerates only if cert is from previous year)
+@reboot root sleep 60 && systemd-cat -t knox-cert-regen ${KNOX_REGEN_SCRIPT}
+EOF
+
+chmod 644 "${KNOX_CRON_FILE}"
+
+emit "Knox certificate auto-renewal configured successfully"
+emit "Cron job created at ${KNOX_CRON_FILE}"
+emit "Certificate year will be checked at 2 AM on January 1st every year and on reboot."
+emit "Certificate will be regenerated only if from a previous year."
+
 #############################
 # Setup instance boot service
 #############################