+.. SPDX-License-Identifier: GPL-2.0
+
+===========
+IPvs-sysctl
+===========
+
/proc/sys/net/ipv4/vs/* Variables:
+==================================
am_droprate - INTEGER
- default 10
+ default 10
- It sets the always mode drop rate, which is used in the mode 3
- of the drop_rate defense.
+ It sets the always mode drop rate, which is used in the mode 3
+ of the drop_rate defense.
amemthresh - INTEGER
- default 1024
+ default 1024
- It sets the available memory threshold (in pages), which is
- used in the automatic modes of defense. When there is no
- enough available memory, the respective strategy will be
- enabled and the variable is automatically set to 2, otherwise
- the strategy is disabled and the variable is set to 1.
+ It sets the available memory threshold (in pages), which is
+ used in the automatic modes of defense. When there is no
+ enough available memory, the respective strategy will be
+ enabled and the variable is automatically set to 2, otherwise
+ the strategy is disabled and the variable is set to 1.
backup_only - BOOLEAN
- 0 - disabled (default)
- not 0 - enabled
+ - 0 - disabled (default)
+ - not 0 - enabled
If set, disable the director function while the server is
in backup mode to avoid packet loops for DR/TUN methods.
real servers to a very busy cluster.
conntrack - BOOLEAN
- 0 - disabled (default)
- not 0 - enabled
+ - 0 - disabled (default)
+ - not 0 - enabled
If set, maintain connection tracking entries for
connections handled by IPVS.
Only available when IPVS is compiled with CONFIG_IP_VS_NFCT enabled.
cache_bypass - BOOLEAN
- 0 - disabled (default)
- not 0 - enabled
+ - 0 - disabled (default)
+ - not 0 - enabled
- If it is enabled, forward packets to the original destination
- directly when no cache server is available and destination
- address is not local (iph->daddr is RTN_UNICAST). It is mostly
- used in transparent web cache cluster.
+ If it is enabled, forward packets to the original destination
+ directly when no cache server is available and destination
+ address is not local (iph->daddr is RTN_UNICAST). It is mostly
+ used in transparent web cache cluster.
debug_level - INTEGER
- 0 - transmission error messages (default)
- 1 - non-fatal error messages
- 2 - configuration
- 3 - destination trash
- 4 - drop entry
- 5 - service lookup
- 6 - scheduling
- 7 - connection new/expire, lookup and synchronization
- 8 - state transition
- 9 - binding destination, template checks and applications
- 10 - IPVS packet transmission
- 11 - IPVS packet handling (ip_vs_in/ip_vs_out)
- 12 or more - packet traversal
+ - 0 - transmission error messages (default)
+ - 1 - non-fatal error messages
+ - 2 - configuration
+ - 3 - destination trash
+ - 4 - drop entry
+ - 5 - service lookup
+ - 6 - scheduling
+ - 7 - connection new/expire, lookup and synchronization
+ - 8 - state transition
+ - 9 - binding destination, template checks and applications
+ - 10 - IPVS packet transmission
+ - 11 - IPVS packet handling (ip_vs_in/ip_vs_out)
+ - 12 or more - packet traversal
Only available when IPVS is compiled with CONFIG_IP_VS_DEBUG enabled.
the level.
drop_entry - INTEGER
- 0 - disabled (default)
-
- The drop_entry defense is to randomly drop entries in the
- connection hash table, just in order to collect back some
- memory for new connections. In the current code, the
- drop_entry procedure can be activated every second, then it
- randomly scans 1/32 of the whole and drops entries that are in
- the SYN-RECV/SYNACK state, which should be effective against
- syn-flooding attack.
-
- The valid values of drop_entry are from 0 to 3, where 0 means
- that this strategy is always disabled, 1 and 2 mean automatic
- modes (when there is no enough available memory, the strategy
- is enabled and the variable is automatically set to 2,
- otherwise the strategy is disabled and the variable is set to
- 1), and 3 means that that the strategy is always enabled.
+ - 0 - disabled (default)
+
+ The drop_entry defense is to randomly drop entries in the
+ connection hash table, just in order to collect back some
+ memory for new connections. In the current code, the
+ drop_entry procedure can be activated every second, then it
+ randomly scans 1/32 of the whole and drops entries that are in
+ the SYN-RECV/SYNACK state, which should be effective against
+ syn-flooding attack.
+
+ The valid values of drop_entry are from 0 to 3, where 0 means
+ that this strategy is always disabled, 1 and 2 mean automatic
+ modes (when there is no enough available memory, the strategy
+ is enabled and the variable is automatically set to 2,
+ otherwise the strategy is disabled and the variable is set to
+ 1), and 3 means that that the strategy is always enabled.
drop_packet - INTEGER
- 0 - disabled (default)
+ - 0 - disabled (default)
- The drop_packet defense is designed to drop 1/rate packets
- before forwarding them to real servers. If the rate is 1, then
- drop all the incoming packets.
+ The drop_packet defense is designed to drop 1/rate packets
+ before forwarding them to real servers. If the rate is 1, then
+ drop all the incoming packets.
- The value definition is the same as that of the drop_entry. In
- the automatic mode, the rate is determined by the follow
- formula: rate = amemthresh / (amemthresh - available_memory)
- when available memory is less than the available memory
- threshold. When the mode 3 is set, the always mode drop rate
- is controlled by the /proc/sys/net/ipv4/vs/am_droprate.
+ The value definition is the same as that of the drop_entry. In
+ the automatic mode, the rate is determined by the follow
+ formula: rate = amemthresh / (amemthresh - available_memory)
+ when available memory is less than the available memory
+ threshold. When the mode 3 is set, the always mode drop rate
+ is controlled by the /proc/sys/net/ipv4/vs/am_droprate.
expire_nodest_conn - BOOLEAN
- 0 - disabled (default)
- not 0 - enabled
-
- The default value is 0, the load balancer will silently drop
- packets when its destination server is not available. It may
- be useful, when user-space monitoring program deletes the
- destination server (because of server overload or wrong
- detection) and add back the server later, and the connections
- to the server can continue.
-
- If this feature is enabled, the load balancer will expire the
- connection immediately when a packet arrives and its
- destination server is not available, then the client program
- will be notified that the connection is closed. This is
- equivalent to the feature some people requires to flush
- connections when its destination is not available.
+ - 0 - disabled (default)
+ - not 0 - enabled
+
+ The default value is 0, the load balancer will silently drop
+ packets when its destination server is not available. It may
+ be useful, when user-space monitoring program deletes the
+ destination server (because of server overload or wrong
+ detection) and add back the server later, and the connections
+ to the server can continue.
+
+ If this feature is enabled, the load balancer will expire the
+ connection immediately when a packet arrives and its
+ destination server is not available, then the client program
+ will be notified that the connection is closed. This is
+ equivalent to the feature some people requires to flush
+ connections when its destination is not available.
expire_quiescent_template - BOOLEAN
- 0 - disabled (default)
- not 0 - enabled
+ - 0 - disabled (default)
+ - not 0 - enabled
When set to a non-zero value, the load balancer will expire
persistent templates when the destination server is quiescent.
connection and the destination server is quiescent.
ignore_tunneled - BOOLEAN
- 0 - disabled (default)
- not 0 - enabled
+ - 0 - disabled (default)
+ - not 0 - enabled
If set, ipvs will set the ipvs_property on all packets which are of
unrecognized protocols. This prevents us from routing tunneled
ipvs routing loops when ipvs is also acting as a real server).
nat_icmp_send - BOOLEAN
- 0 - disabled (default)
- not 0 - enabled
+ - 0 - disabled (default)
+ - not 0 - enabled
- It controls sending icmp error messages (ICMP_DEST_UNREACH)
- for VS/NAT when the load balancer receives packets from real
- servers but the connection entries don't exist.
+ It controls sending icmp error messages (ICMP_DEST_UNREACH)
+ for VS/NAT when the load balancer receives packets from real
+ servers but the connection entries don't exist.
pmtu_disc - BOOLEAN
- 0 - disabled
- not 0 - enabled (default)
+ - 0 - disabled
+ - not 0 - enabled (default)
By default, reject with FRAG_NEEDED all DF packets that exceed
the PMTU, irrespective of the forwarding method. For TUN method
the flag can be disabled to fragment such packets.
secure_tcp - INTEGER
- 0 - disabled (default)
+ - 0 - disabled (default)
The secure_tcp defense is to use a more complicated TCP state
transition table. For VS/NAT, it also delays entering the
TCP ESTABLISHED state until the three way handshake is completed.
- The value definition is the same as that of drop_entry and
- drop_packet.
+ The value definition is the same as that of drop_entry and
+ drop_packet.
sync_threshold - vector of 2 INTEGERs: sync_threshold, sync_period
default 3 50
8848+sync_ports-1.
snat_reroute - BOOLEAN
- 0 - disabled
- not 0 - enabled (default)
+ - 0 - disabled
+ - not 0 - enabled (default)
If enabled, recalculate the route of SNATed packets from
realservers so that they are routed as if they originate from the
Controls the synchronisation of connections when using persistence
0: All types of connections are synchronised
+
1: Attempt to reduce the synchronisation traffic depending on
the connection type. For persistent services avoid synchronisation
for normal connections, do it only for persistence templates.