Enhance DHCP functionality by adding lease time support across various components. Updated DhcpEntryCommand to include lease time, modified VmDhcpConfig to handle lease time, and adjusted related scripts and configurations to accommodate this new parameter. This allows for configurable DHCP lease durations, improving flexibility in network management.

Author: NVShawn

core/src/main/java/com/cloud/agent/api/routing/DhcpEntryCommand.java

@@ -36,6 +36,7 @@ public class DhcpEntryCommand extends NetworkElementCommand {
     private boolean isDefault;
     boolean executeInSequence = false;
     boolean remove;
+    Long leaseTime;
 
     public boolean isRemove() {
         return remove;
@@ -152,4 +153,12 @@ public boolean isDefault() {
     public void setDefault(boolean isDefault) {
         this.isDefault = isDefault;
     }
+
+    public Long getLeaseTime() {
+        return leaseTime;
+    }
+
+    public void setLeaseTime(Long leaseTime) {
+        this.leaseTime = leaseTime;
+    }
 }

core/src/main/java/com/cloud/agent/resource/virtualnetwork/facade/DhcpEntryConfigItem.java

@@ -35,7 +35,7 @@ public List<ConfigItem> generateConfig(final NetworkElementCommand cmd) {
         final DhcpEntryCommand command = (DhcpEntryCommand) cmd;
 
         final VmDhcpConfig vmDhcpConfig = new VmDhcpConfig(command.getVmName(), command.getVmMac(), command.getVmIpAddress(), command.getVmIp6Address(), command.getDuid(), command.getDefaultDns(),
-                command.getDefaultRouter(), command.getStaticRoutes(), command.isDefault(), command.isRemove());
+                command.getDefaultRouter(), command.getStaticRoutes(), command.isDefault(), command.isRemove(), command.getLeaseTime());
 
         return generateConfigItems(vmDhcpConfig);
     }

core/src/main/java/com/cloud/agent/resource/virtualnetwork/model/VmDhcpConfig.java

@@ -29,6 +29,7 @@ public class VmDhcpConfig extends ConfigBase {
     private String defaultGateway;
     private String staticRoutes;
     private boolean defaultEntry;
+    private Long leaseTime;
 
     // Indicate if the entry should be removed when set to true
     private boolean remove;
@@ -39,6 +40,11 @@ public VmDhcpConfig() {
 
     public VmDhcpConfig(String hostName, String macAddress, String ipv4Address, String ipv6Address, String ipv6Duid, String dnsAddresses, String defaultGateway,
             String staticRoutes, boolean defaultEntry, boolean remove) {
+        this(hostName, macAddress, ipv4Address, ipv6Address, ipv6Duid, dnsAddresses, defaultGateway, staticRoutes, defaultEntry, remove, null);
+    }
+
+    public VmDhcpConfig(String hostName, String macAddress, String ipv4Address, String ipv6Address, String ipv6Duid, String dnsAddresses, String defaultGateway,
+            String staticRoutes, boolean defaultEntry, boolean remove, Long leaseTime) {
         super(VM_DHCP);
         this.hostName = hostName;
         this.macAddress = macAddress;
@@ -50,6 +56,7 @@ public VmDhcpConfig(String hostName, String macAddress, String ipv4Address, Stri
         this.staticRoutes = staticRoutes;
         this.defaultEntry = defaultEntry;
         this.remove = remove;
+        this.leaseTime = leaseTime;
     }
 
     public String getHostName() {
@@ -132,4 +139,12 @@ public void setDefaultEntry(boolean defaultEntry) {
         this.defaultEntry = defaultEntry;
     }
 
+    public Long getLeaseTime() {
+        return leaseTime;
+    }
+
+    public void setLeaseTime(Long leaseTime) {
+        this.leaseTime = leaseTime;
+    }
+
 }

scripts/network/exdhcp/dhcpd_edithosts.py

@@ -17,18 +17,18 @@
 # under the License.
 
 
-# Usage: dhcpd_edithosts.py mac ip hostname dns gateway nextserver
+# Usage: dhcpd_edithosts.py mac ip hostname dns gateway nextserver [leasetime]
 import sys, os
 from os.path import exists
 from time import sleep
 from os import remove
 
-usage = '''dhcpd_edithosts.py mac ip hostname dns gateway nextserver'''
+usage = '''dhcpd_edithosts.py mac ip hostname dns gateway nextserver [leasetime]'''
 conf_path = "/etc/dhcpd.conf"
 file_lock = "/etc/dhcpd.conf_locked"
 sleep_max = 20
-host_entry = 'host %s { hardware ethernet %s; fixed-address %s; option domain-name-servers %s; option domain-name "%s"; option routers %s; default-lease-time infinite; max-lease-time infinite; min-lease-time infinite; filename "pxelinux.0";}'
-host_entry1 = 'host %s { hardware ethernet %s; fixed-address %s; option domain-name-servers %s; option domain-name "%s"; option routers %s; default-lease-time infinite; max-lease-time infinite; min-lease-time infinite; next-server %s; filename "pxelinux.0";}'
+host_entry = 'host %s { hardware ethernet %s; fixed-address %s; option domain-name-servers %s; option domain-name "%s"; option routers %s; default-lease-time %s; max-lease-time %s; min-lease-time %s; filename "pxelinux.0";}'
+host_entry1 = 'host %s { hardware ethernet %s; fixed-address %s; option domain-name-servers %s; option domain-name "%s"; option routers %s; default-lease-time %s; max-lease-time %s; min-lease-time %s; next-server %s; filename "pxelinux.0";}'
 def lock():
 	if exists(file_lock):
 		count = 0
@@ -59,10 +59,14 @@ def unlock():
 			print "Cannot remove file lock at %s" % file_lock
 			return False
 
-def insert_host_entry(mac, ip, hostname, dns, gateway, next_server):
+def insert_host_entry(mac, ip, hostname, dns, gateway, next_server, lease_time="infinite"):
 	if lock() == False:
 		return 1
 
+	# Convert 0 to 'infinite' for lease time
+	if lease_time == "0":
+		lease_time = "infinite"
+
 	cmd = 'sed -i /"fixed-address %s"/d %s' % (ip, conf_path)
 	ret = os.system(cmd)
 	if ret != 0:
@@ -78,9 +82,9 @@ def insert_host_entry(mac, ip, hostname, dns, gateway, next_server):
 		return 1
 
 	if next_server != "null":
-		entry = host_entry1 % (hostname, mac, ip, dns, "cloudnine.internal", gateway, next_server)
+		entry = host_entry1 % (hostname, mac, ip, dns, "cloudnine.internal", gateway, lease_time, lease_time, lease_time, next_server)
 	else:
-		entry = host_entry % (hostname, mac, ip, dns, "cloudnine.internal", gateway)
+		entry = host_entry % (hostname, mac, ip, dns, "cloudnine.internal", gateway, lease_time, lease_time, lease_time)
 	cmd = '''echo '%s' >> %s''' % (entry, conf_path)
 	ret = os.system(cmd)
 	if ret != 0:
@@ -111,12 +115,13 @@ def insert_host_entry(mac, ip, hostname, dns, gateway, next_server):
 	dns = sys.argv[4]
 	gateway = sys.argv[5]
 	next_server = sys.argv[6]
+	lease_time = sys.argv[7] if len(sys.argv) > 7 else "infinite"
 
 	if exists(conf_path) == False:
 		conf_path = "/etc/dhcp/dhcpd.conf"
 	if exists(conf_path) == False:
 		print "Cannot find dhcpd.conf"
 		sys.exit(1)
 
-	ret = insert_host_entry(mac, ip, hostname, dns, gateway, next_server)
+	ret = insert_host_entry(mac, ip, hostname, dns, gateway, next_server, lease_time)
 	sys.exit(ret)

scripts/network/exdhcp/dnsmasq_edithosts.sh

@@ -21,6 +21,7 @@
 # $1 : the mac address
 # $2 : the associated ip address
 # $3 : the hostname
+# $4 : the lease time (optional, defaults to 'infinite')
 
 wait_for_dnsmasq () {
   local _pid=$(pidof dnsmasq)
@@ -41,11 +42,17 @@ no_dhcp_release=$?
 [ ! -f /etc/dhcphosts.txt ] && touch /etc/dhcphosts.txt
 [ ! -f /var/lib/misc/dnsmasq.leases ] && touch /var/lib/misc/dnsmasq.leases
 
+# Set lease time, default to 'infinite', convert 0 to 'infinite'
+lease_time=${4:-infinite}
+if [ "$lease_time" = "0" ]; then
+  lease_time=infinite
+fi
+
 sed -i  /$1/d /etc/dhcphosts.txt
 sed -i  /$2,/d /etc/dhcphosts.txt
 sed -i  /$3,/d /etc/dhcphosts.txt
 
-echo "$1,$2,$3,infinite" >>/etc/dhcphosts.txt
+echo "$1,$2,$3,$lease_time" >>/etc/dhcphosts.txt
 
 #release previous dhcp lease if present
 if [ $no_dhcp_release -eq 0 ]

server/src/main/java/com/cloud/configuration/Config.java

@@ -351,6 +351,15 @@ public enum Config {
             ConfigKey.Kind.CSV,
             null),
 
+    DhcpLeaseTimeout(
+            "Network",
+            ManagementServer.class,
+            Integer.class,
+            "dhcp.lease.timeout",
+            "0",
+            "DHCP lease time in seconds for VMs. Use 0 for infinite lease time (default). A non-zero value sets the lease duration in seconds.",
+            null),
+
     //VPN
     RemoteAccessVpnPskLength(
             "Network",

server/src/main/java/com/cloud/network/router/CommandSetupHelper.java

@@ -296,6 +296,11 @@ public void createDhcpEntryCommand(final VirtualRouter router, final UserVm vm,
         dhcpCommand.setDefault(nic.isDefaultNic());
         dhcpCommand.setRemove(remove);
 
+        // Set DHCP lease timeout from global config (0 = infinite)
+        String leaseTimeStr = _configDao.getValue(Config.DhcpLeaseTimeout.key());
+        Long leaseTime = (leaseTimeStr != null) ? Long.parseLong(leaseTimeStr) : 0L;
+        dhcpCommand.setLeaseTime(leaseTime);
+
         dhcpCommand.setAccessDetail(NetworkElementCommand.ROUTER_IP, _routerControlHelper.getRouterControlIp(router.getId()));
         dhcpCommand.setAccessDetail(NetworkElementCommand.ROUTER_NAME, router.getInstanceName());
         dhcpCommand.setAccessDetail(NetworkElementCommand.ROUTER_GUEST_IP, _routerControlHelper.getRouterIpInNetwork(nic.getNetworkId(), router.getId()));

systemvm/debian/opt/cloud/bin/cs/CsDhcp.py

@@ -199,12 +199,14 @@ def write_hosts(self):
 
     def add(self, entry):
         self.add_host(entry['ipv4_address'], entry['host_name'])
-        # Lease time set to "infinite" since we properly control all DHCP/DNS config via CloudStack.
+        # Lease time is configurable via CloudStack global config dhcp.lease.timeout
+        # 0 = infinite (default), otherwise the value represents seconds
         # Infinite time helps avoid some edge cases which could cause DHCPNAK being sent to VMs since
         # (RHEL) system lose routes when they receive DHCPNAK.
         # When VM is expunged, its active lease and DHCP/DNS config is properly removed from related files in VR,
         # so the infinite duration of lease does not cause any issues or garbage.
-        lease = 'infinite'
+        lease_time = entry.get('lease_time', 0)
+        lease = 'infinite' if lease_time == 0 else str(lease_time)
 
         if entry['default_entry']:
             self.dhcp_hosts.add("%s,%s,%s,%s" % (entry['mac_address'],

systemvm/debian/opt/cloud/bin/edithosts.sh

@@ -21,7 +21,7 @@
 # edithosts.sh -- edit the dhcphosts file on the routing domain
 
 usage() {
-  printf "Usage: %s: -m <MAC address> -4 <IPv4 address> -6 <IPv6 address> -h <hostname> -d <default router> -n <name server address> -s <Routes> -u <DUID> [-N]\n" $(basename $0) >&2
+  printf "Usage: %s: -m <MAC address> -4 <IPv4 address> -6 <IPv6 address> -h <hostname> -d <default router> -n <name server address> -s <Routes> -u <DUID> -l <lease time> [-N]\n" $(basename $0) >&2
 }
 
 mac=
@@ -33,8 +33,9 @@ dns=
 routes=
 duid=
 nondefault=
+lease_time=infinite
 
-while getopts 'm:4:h:d:n:s:6:u:N' OPTION
+while getopts 'm:4:h:d:n:s:6:u:l:N' OPTION
 do
   case $OPTION in
   m)    mac="$OPTARG"
@@ -53,6 +54,8 @@ do
         ;;
   s)    routes="$OPTARG"
         ;;
+  l)    lease_time="$OPTARG"
+        ;;
   N)    nondefault=1
         ;;
   ?)    usage
@@ -124,17 +127,21 @@ fi
 sed -i  /$host,/d $DHCP_HOSTS
 
 #put in the new entry
+# If lease_time is 0, use 'infinite', otherwise use the value
+if [ "$lease_time" = "0" ]; then
+  lease_time=infinite
+fi
 if [ $ipv4 ]
 then
-  echo "$mac,$ipv4,$host,infinite" >>$DHCP_HOSTS
+  echo "$mac,$ipv4,$host,$lease_time" >>$DHCP_HOSTS
 fi
 if [ $ipv6 ]
 then
   if [ $nondefault ]
   then
-    echo "id:$duid,set:nondefault6,[$ipv6],$host,infinite" >>$DHCP_HOSTS
+    echo "id:$duid,set:nondefault6,[$ipv6],$host,$lease_time" >>$DHCP_HOSTS
   else
-    echo "id:$duid,[$ipv6],$host,infinite" >>$DHCP_HOSTS
+    echo "id:$duid,[$ipv6],$host,$lease_time" >>$DHCP_HOSTS
   fi
 fi