mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-21 11:44:01 +08:00
3c679cba58
Document sysctl pmtu_disc based on commit 3654e61137 ("ipvs: add
pmtu_disc option to disable IP DF for TUN packets").
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
295 lines
11 KiB
Plaintext
295 lines
11 KiB
Plaintext
/proc/sys/net/ipv4/vs/* Variables:
|
|
|
|
am_droprate - INTEGER
|
|
default 10
|
|
|
|
It sets the always mode drop rate, which is used in the mode 3
|
|
of the drop_rate defense.
|
|
|
|
amemthresh - INTEGER
|
|
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.
|
|
|
|
backup_only - BOOLEAN
|
|
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.
|
|
|
|
conn_reuse_mode - INTEGER
|
|
1 - default
|
|
|
|
Controls how ipvs will deal with connections that are detected
|
|
port reuse. It is a bitmap, with the values being:
|
|
|
|
0: disable any special handling on port reuse. The new
|
|
connection will be delivered to the same real server that was
|
|
servicing the previous connection. This will effectively
|
|
disable expire_nodest_conn.
|
|
|
|
bit 1: enable rescheduling of new connections when it is safe.
|
|
That is, whenever expire_nodest_conn and for TCP sockets, when
|
|
the connection is in TIME_WAIT state (which is only possible if
|
|
you use NAT mode).
|
|
|
|
bit 2: it is bit 1 plus, for TCP connections, when connections
|
|
are in FIN_WAIT state, as this is the last state seen by load
|
|
balancer in Direct Routing mode. This bit helps on adding new
|
|
real servers to a very busy cluster.
|
|
|
|
conntrack - BOOLEAN
|
|
0 - disabled (default)
|
|
not 0 - enabled
|
|
|
|
If set, maintain connection tracking entries for
|
|
connections handled by IPVS.
|
|
|
|
This should be enabled if connections handled by IPVS are to be
|
|
also handled by stateful firewall rules. That is, iptables rules
|
|
that make use of connection tracking. It is a performance
|
|
optimisation to disable this setting otherwise.
|
|
|
|
Connections handled by the IPVS FTP application module
|
|
will have connection tracking entries regardless of this setting.
|
|
|
|
Only available when IPVS is compiled with CONFIG_IP_VS_NFCT enabled.
|
|
|
|
cache_bypass - BOOLEAN
|
|
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.
|
|
|
|
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
|
|
|
|
Only available when IPVS is compiled with CONFIG_IP_VS_DEBUG enabled.
|
|
|
|
Higher debugging levels include the messages for lower debugging
|
|
levels, so setting debug level 2, includes level 0, 1 and 2
|
|
messages. Thus, logging becomes more and more verbose the higher
|
|
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.
|
|
|
|
drop_packet - INTEGER
|
|
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 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.
|
|
|
|
expire_quiescent_template - BOOLEAN
|
|
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.
|
|
This may be useful, when a user makes a destination server
|
|
quiescent by setting its weight to 0 and it is desired that
|
|
subsequent otherwise persistent connections are sent to a
|
|
different destination server. By default new persistent
|
|
connections are allowed to quiescent destination servers.
|
|
|
|
If this feature is enabled, the load balancer will expire the
|
|
persistence template if it is to be used to schedule a new
|
|
connection and the destination server is quiescent.
|
|
|
|
ignore_tunneled - BOOLEAN
|
|
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
|
|
protocols like ipip, which is useful to prevent rescheduling
|
|
packets that have been tunneled to the ipvs host (i.e. to prevent
|
|
ipvs routing loops when ipvs is also acting as a real server).
|
|
|
|
nat_icmp_send - BOOLEAN
|
|
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.
|
|
|
|
pmtu_disc - BOOLEAN
|
|
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)
|
|
|
|
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.
|
|
|
|
sync_threshold - vector of 2 INTEGERs: sync_threshold, sync_period
|
|
default 3 50
|
|
|
|
It sets synchronization threshold, which is the minimum number
|
|
of incoming packets that a connection needs to receive before
|
|
the connection will be synchronized. A connection will be
|
|
synchronized, every time the number of its incoming packets
|
|
modulus sync_period equals the threshold. The range of the
|
|
threshold is from 0 to sync_period.
|
|
|
|
When sync_period and sync_refresh_period are 0, send sync only
|
|
for state changes or only once when pkts matches sync_threshold
|
|
|
|
sync_refresh_period - UNSIGNED INTEGER
|
|
default 0
|
|
|
|
In seconds, difference in reported connection timer that triggers
|
|
new sync message. It can be used to avoid sync messages for the
|
|
specified period (or half of the connection timeout if it is lower)
|
|
if connection state is not changed since last sync.
|
|
|
|
This is useful for normal connections with high traffic to reduce
|
|
sync rate. Additionally, retry sync_retries times with period of
|
|
sync_refresh_period/8.
|
|
|
|
sync_retries - INTEGER
|
|
default 0
|
|
|
|
Defines sync retries with period of sync_refresh_period/8. Useful
|
|
to protect against loss of sync messages. The range of the
|
|
sync_retries is from 0 to 3.
|
|
|
|
sync_qlen_max - UNSIGNED LONG
|
|
|
|
Hard limit for queued sync messages that are not sent yet. It
|
|
defaults to 1/32 of the memory pages but actually represents
|
|
number of messages. It will protect us from allocating large
|
|
parts of memory when the sending rate is lower than the queuing
|
|
rate.
|
|
|
|
sync_sock_size - INTEGER
|
|
default 0
|
|
|
|
Configuration of SNDBUF (master) or RCVBUF (slave) socket limit.
|
|
Default value is 0 (preserve system defaults).
|
|
|
|
sync_ports - INTEGER
|
|
default 1
|
|
|
|
The number of threads that master and backup servers can use for
|
|
sync traffic. Every thread will use single UDP port, thread 0 will
|
|
use the default port 8848 while last thread will use port
|
|
8848+sync_ports-1.
|
|
|
|
snat_reroute - BOOLEAN
|
|
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
|
|
director. Otherwise they are routed as if they are forwarded by the
|
|
director.
|
|
|
|
If policy routing is in effect then it is possible that the route
|
|
of a packet originating from a director is routed differently to a
|
|
packet being forwarded by the director.
|
|
|
|
If policy routing is not in effect then the recalculated route will
|
|
always be the same as the original route so it is an optimisation
|
|
to disable snat_reroute and avoid the recalculation.
|
|
|
|
sync_persist_mode - INTEGER
|
|
default 0
|
|
|
|
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.
|
|
In such case, for TCP and SCTP it may need enabling sloppy_tcp and
|
|
sloppy_sctp flags on backup servers. For non-persistent services
|
|
such optimization is not applied, mode 0 is assumed.
|
|
|
|
sync_version - INTEGER
|
|
default 1
|
|
|
|
The version of the synchronisation protocol used when sending
|
|
synchronisation messages.
|
|
|
|
0 selects the original synchronisation protocol (version 0). This
|
|
should be used when sending synchronisation messages to a legacy
|
|
system that only understands the original synchronisation protocol.
|
|
|
|
1 selects the current synchronisation protocol (version 1). This
|
|
should be used where possible.
|
|
|
|
Kernels with this sync_version entry are able to receive messages
|
|
of both version 1 and version 2 of the synchronisation protocol.
|