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82a07bf3 MCC |
1 | .. SPDX-License-Identifier: GPL-2.0 |
2 | ||
3 | =========== | |
4 | IPvs-sysctl | |
5 | =========== | |
6 | ||
6ce1669f | 7 | /proc/sys/net/ipv4/vs/* Variables: |
82a07bf3 | 8 | ================================== |
6ce1669f H |
9 | |
10 | am_droprate - INTEGER | |
82a07bf3 | 11 | default 10 |
6ce1669f | 12 | |
82a07bf3 MCC |
13 | It sets the always mode drop rate, which is used in the mode 3 |
14 | of the drop_rate defense. | |
6ce1669f H |
15 | |
16 | amemthresh - INTEGER | |
82a07bf3 | 17 | default 1024 |
6ce1669f | 18 | |
82a07bf3 MCC |
19 | It sets the available memory threshold (in pages), which is |
20 | used in the automatic modes of defense. When there is no | |
21 | enough available memory, the respective strategy will be | |
22 | enabled and the variable is automatically set to 2, otherwise | |
23 | the strategy is disabled and the variable is set to 1. | |
6ce1669f | 24 | |
0c12582f | 25 | backup_only - BOOLEAN |
82a07bf3 MCC |
26 | - 0 - disabled (default) |
27 | - not 0 - enabled | |
0c12582f JA |
28 | |
29 | If set, disable the director function while the server is | |
30 | in backup mode to avoid packet loops for DR/TUN methods. | |
31 | ||
d752c364 MRL |
32 | conn_reuse_mode - INTEGER |
33 | 1 - default | |
34 | ||
35 | Controls how ipvs will deal with connections that are detected | |
36 | port reuse. It is a bitmap, with the values being: | |
37 | ||
38 | 0: disable any special handling on port reuse. The new | |
39 | connection will be delivered to the same real server that was | |
40 | servicing the previous connection. This will effectively | |
41 | disable expire_nodest_conn. | |
42 | ||
43 | bit 1: enable rescheduling of new connections when it is safe. | |
44 | That is, whenever expire_nodest_conn and for TCP sockets, when | |
45 | the connection is in TIME_WAIT state (which is only possible if | |
46 | you use NAT mode). | |
47 | ||
48 | bit 2: it is bit 1 plus, for TCP connections, when connections | |
49 | are in FIN_WAIT state, as this is the last state seen by load | |
50 | balancer in Direct Routing mode. This bit helps on adding new | |
51 | real servers to a very busy cluster. | |
52 | ||
7e777dd4 | 53 | conntrack - BOOLEAN |
82a07bf3 MCC |
54 | - 0 - disabled (default) |
55 | - not 0 - enabled | |
7e777dd4 SH |
56 | |
57 | If set, maintain connection tracking entries for | |
58 | connections handled by IPVS. | |
59 | ||
60 | This should be enabled if connections handled by IPVS are to be | |
61 | also handled by stateful firewall rules. That is, iptables rules | |
62 | that make use of connection tracking. It is a performance | |
63 | optimisation to disable this setting otherwise. | |
64 | ||
65 | Connections handled by the IPVS FTP application module | |
66 | will have connection tracking entries regardless of this setting. | |
67 | ||
40cb1f9b | 68 | Only available when IPVS is compiled with CONFIG_IP_VS_NFCT enabled. |
7e777dd4 | 69 | |
6ce1669f | 70 | cache_bypass - BOOLEAN |
82a07bf3 MCC |
71 | - 0 - disabled (default) |
72 | - not 0 - enabled | |
6ce1669f | 73 | |
82a07bf3 MCC |
74 | If it is enabled, forward packets to the original destination |
75 | directly when no cache server is available and destination | |
76 | address is not local (iph->daddr is RTN_UNICAST). It is mostly | |
77 | used in transparent web cache cluster. | |
6ce1669f H |
78 | |
79 | debug_level - INTEGER | |
82a07bf3 MCC |
80 | - 0 - transmission error messages (default) |
81 | - 1 - non-fatal error messages | |
82 | - 2 - configuration | |
83 | - 3 - destination trash | |
84 | - 4 - drop entry | |
85 | - 5 - service lookup | |
86 | - 6 - scheduling | |
87 | - 7 - connection new/expire, lookup and synchronization | |
88 | - 8 - state transition | |
89 | - 9 - binding destination, template checks and applications | |
90 | - 10 - IPVS packet transmission | |
91 | - 11 - IPVS packet handling (ip_vs_in/ip_vs_out) | |
92 | - 12 or more - packet traversal | |
6ce1669f | 93 | |
40cb1f9b | 94 | Only available when IPVS is compiled with CONFIG_IP_VS_DEBUG enabled. |
6ce1669f H |
95 | |
96 | Higher debugging levels include the messages for lower debugging | |
97 | levels, so setting debug level 2, includes level 0, 1 and 2 | |
98 | messages. Thus, logging becomes more and more verbose the higher | |
99 | the level. | |
100 | ||
101 | drop_entry - INTEGER | |
82a07bf3 MCC |
102 | - 0 - disabled (default) |
103 | ||
104 | The drop_entry defense is to randomly drop entries in the | |
105 | connection hash table, just in order to collect back some | |
106 | memory for new connections. In the current code, the | |
107 | drop_entry procedure can be activated every second, then it | |
108 | randomly scans 1/32 of the whole and drops entries that are in | |
109 | the SYN-RECV/SYNACK state, which should be effective against | |
110 | syn-flooding attack. | |
111 | ||
112 | The valid values of drop_entry are from 0 to 3, where 0 means | |
113 | that this strategy is always disabled, 1 and 2 mean automatic | |
114 | modes (when there is no enough available memory, the strategy | |
115 | is enabled and the variable is automatically set to 2, | |
116 | otherwise the strategy is disabled and the variable is set to | |
474112d5 | 117 | 1), and 3 means that the strategy is always enabled. |
6ce1669f H |
118 | |
119 | drop_packet - INTEGER | |
82a07bf3 | 120 | - 0 - disabled (default) |
6ce1669f | 121 | |
82a07bf3 MCC |
122 | The drop_packet defense is designed to drop 1/rate packets |
123 | before forwarding them to real servers. If the rate is 1, then | |
124 | drop all the incoming packets. | |
6ce1669f | 125 | |
82a07bf3 MCC |
126 | The value definition is the same as that of the drop_entry. In |
127 | the automatic mode, the rate is determined by the follow | |
128 | formula: rate = amemthresh / (amemthresh - available_memory) | |
129 | when available memory is less than the available memory | |
130 | threshold. When the mode 3 is set, the always mode drop rate | |
131 | is controlled by the /proc/sys/net/ipv4/vs/am_droprate. | |
6ce1669f H |
132 | |
133 | expire_nodest_conn - BOOLEAN | |
82a07bf3 MCC |
134 | - 0 - disabled (default) |
135 | - not 0 - enabled | |
136 | ||
137 | The default value is 0, the load balancer will silently drop | |
138 | packets when its destination server is not available. It may | |
139 | be useful, when user-space monitoring program deletes the | |
140 | destination server (because of server overload or wrong | |
141 | detection) and add back the server later, and the connections | |
142 | to the server can continue. | |
143 | ||
144 | If this feature is enabled, the load balancer will expire the | |
145 | connection immediately when a packet arrives and its | |
146 | destination server is not available, then the client program | |
147 | will be notified that the connection is closed. This is | |
148 | equivalent to the feature some people requires to flush | |
149 | connections when its destination is not available. | |
6ce1669f H |
150 | |
151 | expire_quiescent_template - BOOLEAN | |
82a07bf3 MCC |
152 | - 0 - disabled (default) |
153 | - not 0 - enabled | |
6ce1669f H |
154 | |
155 | When set to a non-zero value, the load balancer will expire | |
156 | persistent templates when the destination server is quiescent. | |
157 | This may be useful, when a user makes a destination server | |
158 | quiescent by setting its weight to 0 and it is desired that | |
159 | subsequent otherwise persistent connections are sent to a | |
160 | different destination server. By default new persistent | |
161 | connections are allowed to quiescent destination servers. | |
162 | ||
163 | If this feature is enabled, the load balancer will expire the | |
164 | persistence template if it is to be used to schedule a new | |
165 | connection and the destination server is quiescent. | |
166 | ||
4e478098 | 167 | ignore_tunneled - BOOLEAN |
82a07bf3 MCC |
168 | - 0 - disabled (default) |
169 | - not 0 - enabled | |
4e478098 AG |
170 | |
171 | If set, ipvs will set the ipvs_property on all packets which are of | |
172 | unrecognized protocols. This prevents us from routing tunneled | |
173 | protocols like ipip, which is useful to prevent rescheduling | |
174 | packets that have been tunneled to the ipvs host (i.e. to prevent | |
175 | ipvs routing loops when ipvs is also acting as a real server). | |
176 | ||
6ce1669f | 177 | nat_icmp_send - BOOLEAN |
82a07bf3 MCC |
178 | - 0 - disabled (default) |
179 | - not 0 - enabled | |
6ce1669f | 180 | |
82a07bf3 MCC |
181 | It controls sending icmp error messages (ICMP_DEST_UNREACH) |
182 | for VS/NAT when the load balancer receives packets from real | |
183 | servers but the connection entries don't exist. | |
6ce1669f | 184 | |
3c679cba | 185 | pmtu_disc - BOOLEAN |
82a07bf3 MCC |
186 | - 0 - disabled |
187 | - not 0 - enabled (default) | |
3c679cba HL |
188 | |
189 | By default, reject with FRAG_NEEDED all DF packets that exceed | |
190 | the PMTU, irrespective of the forwarding method. For TUN method | |
191 | the flag can be disabled to fragment such packets. | |
192 | ||
6ce1669f | 193 | secure_tcp - INTEGER |
82a07bf3 | 194 | - 0 - disabled (default) |
6ce1669f | 195 | |
325aadc8 SH |
196 | The secure_tcp defense is to use a more complicated TCP state |
197 | transition table. For VS/NAT, it also delays entering the | |
198 | TCP ESTABLISHED state until the three way handshake is completed. | |
6ce1669f | 199 | |
82a07bf3 MCC |
200 | The value definition is the same as that of drop_entry and |
201 | drop_packet. | |
6ce1669f | 202 | |
a2f346d8 HL |
203 | sync_threshold - vector of 2 INTEGERs: sync_threshold, sync_period |
204 | default 3 50 | |
205 | ||
206 | It sets synchronization threshold, which is the minimum number | |
207 | of incoming packets that a connection needs to receive before | |
208 | the connection will be synchronized. A connection will be | |
209 | synchronized, every time the number of its incoming packets | |
210 | modulus sync_period equals the threshold. The range of the | |
211 | threshold is from 0 to sync_period. | |
212 | ||
213 | When sync_period and sync_refresh_period are 0, send sync only | |
214 | for state changes or only once when pkts matches sync_threshold | |
215 | ||
216 | sync_refresh_period - UNSIGNED INTEGER | |
217 | default 0 | |
218 | ||
219 | In seconds, difference in reported connection timer that triggers | |
220 | new sync message. It can be used to avoid sync messages for the | |
221 | specified period (or half of the connection timeout if it is lower) | |
222 | if connection state is not changed since last sync. | |
223 | ||
224 | This is useful for normal connections with high traffic to reduce | |
225 | sync rate. Additionally, retry sync_retries times with period of | |
226 | sync_refresh_period/8. | |
227 | ||
228 | sync_retries - INTEGER | |
229 | default 0 | |
230 | ||
231 | Defines sync retries with period of sync_refresh_period/8. Useful | |
232 | to protect against loss of sync messages. The range of the | |
233 | sync_retries is from 0 to 3. | |
7e777dd4 | 234 | |
237e5722 HL |
235 | sync_qlen_max - UNSIGNED LONG |
236 | ||
237 | Hard limit for queued sync messages that are not sent yet. It | |
238 | defaults to 1/32 of the memory pages but actually represents | |
239 | number of messages. It will protect us from allocating large | |
240 | parts of memory when the sending rate is lower than the queuing | |
241 | rate. | |
242 | ||
243 | sync_sock_size - INTEGER | |
244 | default 0 | |
245 | ||
246 | Configuration of SNDBUF (master) or RCVBUF (slave) socket limit. | |
247 | Default value is 0 (preserve system defaults). | |
248 | ||
24b44415 HL |
249 | sync_ports - INTEGER |
250 | default 1 | |
251 | ||
252 | The number of threads that master and backup servers can use for | |
253 | sync traffic. Every thread will use single UDP port, thread 0 will | |
254 | use the default port 8848 while last thread will use port | |
255 | 8848+sync_ports-1. | |
256 | ||
7e777dd4 | 257 | snat_reroute - BOOLEAN |
82a07bf3 MCC |
258 | - 0 - disabled |
259 | - not 0 - enabled (default) | |
7e777dd4 SH |
260 | |
261 | If enabled, recalculate the route of SNATed packets from | |
262 | realservers so that they are routed as if they originate from the | |
263 | director. Otherwise they are routed as if they are forwarded by the | |
264 | director. | |
265 | ||
266 | If policy routing is in effect then it is possible that the route | |
267 | of a packet originating from a director is routed differently to a | |
268 | packet being forwarded by the director. | |
269 | ||
270 | If policy routing is not in effect then the recalculated route will | |
271 | always be the same as the original route so it is an optimisation | |
272 | to disable snat_reroute and avoid the recalculation. | |
273 | ||
4d0c875d JA |
274 | sync_persist_mode - INTEGER |
275 | default 0 | |
276 | ||
277 | Controls the synchronisation of connections when using persistence | |
278 | ||
279 | 0: All types of connections are synchronised | |
82a07bf3 | 280 | |
4d0c875d JA |
281 | 1: Attempt to reduce the synchronisation traffic depending on |
282 | the connection type. For persistent services avoid synchronisation | |
283 | for normal connections, do it only for persistence templates. | |
284 | In such case, for TCP and SCTP it may need enabling sloppy_tcp and | |
285 | sloppy_sctp flags on backup servers. For non-persistent services | |
286 | such optimization is not applied, mode 0 is assumed. | |
287 | ||
7e777dd4 SH |
288 | sync_version - INTEGER |
289 | default 1 | |
290 | ||
291 | The version of the synchronisation protocol used when sending | |
292 | synchronisation messages. | |
293 | ||
294 | 0 selects the original synchronisation protocol (version 0). This | |
295 | should be used when sending synchronisation messages to a legacy | |
296 | system that only understands the original synchronisation protocol. | |
297 | ||
298 | 1 selects the current synchronisation protocol (version 1). This | |
299 | should be used where possible. | |
300 | ||
301 | Kernels with this sync_version entry are able to receive messages | |
302 | of both version 1 and version 2 of the synchronisation protocol. | |
2232642e DL |
303 | |
304 | run_estimation - BOOLEAN | |
305 | 0 - disabled | |
306 | not 0 - enabled (default) | |
307 | ||
308 | If disabled, the estimation will be stop, and you can't see | |
309 | any update on speed estimation data. | |
310 | ||
311 | You can always re-enable estimation by setting this value to 1. | |
312 | But be careful, the first estimation after re-enable is not | |
313 | accurate. |