Hello,
On Tue, 28 May 2013, Aleksey Chudov wrote:
> Currently we are using multiple active / standby server pairs and synchronize
> them with each other. So half of the servers are constantly doing nothing. We
> are searching how to use all the servers in active / active mode while
> maintaining high availability and sessions persistence in case of failure of
> one of the load balancers. Unfortunately the proposed stateless scheme with SH
> scheduler and Sloppy TCP is not suitable for as since we are using WLC and WRR
> schedulers. As you mentioned SH scheduler has several drawbacks because of
> which we can not use it. Also, we can not synchronize all connections between
> all servers, since it would require a lot of memory and the search for such a
> huge connection table is likely to be slower.
>
> But we can solve the sync problem in such a way as done in the conntrackd
> which allows filtering by flow state. The easiest option is to make the filter
> only for IP_VS_CONN_F_TEMPLATE state. Thus if all the load balancers will sync
> persistent templates with each other then even if one of the load balancers
> fails most users will remain on the same real servers. Of course without the
> full sync clients must reestablish TCP connections, but for this case we can
> use Sloppy TCP to create a TCP connection state on any TCP packet.
>
> What do you think of this idea?
Here is something that is compile-tested. You
will need the "ipvs: sloppy TCP and SCTP" patch by
Alexander Frolkin posted on 13 Jun. Let me know if
you need more help in applying and testing such patches,
so that we can be more confident when releasing such
optimization officially.
From: Julian Anastasov <ja@xxxxxx>
[PATCH] ipvs: add sync_persist_mode flag
Add sync_persist_mode flag to reduce sync traffic
by syncing only persistent templates.
Signed-off-by: Julian Anastasov <ja@xxxxxx>
---
Documentation/networking/ipvs-sysctl.txt | 13 +++++++++++++
include/net/ip_vs.h | 11 +++++++++++
net/netfilter/ipvs/ip_vs_ctl.c | 7 +++++++
net/netfilter/ipvs/ip_vs_sync.c | 12 ++++++++++++
4 files changed, 43 insertions(+), 0 deletions(-)
diff --git a/Documentation/networking/ipvs-sysctl.txt b/Documentation/networking/ipvs-sysctl.txt
index 9573d0c..7a3c047 100644
--- a/Documentation/networking/ipvs-sysctl.txt
+++ b/Documentation/networking/ipvs-sysctl.txt
@@ -181,6 +181,19 @@ snat_reroute - BOOLEAN
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
diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index e667df1..f0d70f0 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h
@@ -975,6 +975,7 @@ struct netns_ipvs {
int sysctl_snat_reroute;
int sysctl_sync_ver;
int sysctl_sync_ports;
+ int sysctl_sync_persist_mode;
unsigned long sysctl_sync_qlen_max;
int sysctl_sync_sock_size;
int sysctl_cache_bypass;
@@ -1076,6 +1077,11 @@ static inline int sysctl_sync_ports(struct netns_ipvs *ipvs)
return ACCESS_ONCE(ipvs->sysctl_sync_ports);
}
+static inline int sysctl_sync_persist_mode(struct netns_ipvs *ipvs)
+{
+ return ipvs->sysctl_sync_persist_mode;
+}
+
static inline unsigned long sysctl_sync_qlen_max(struct netns_ipvs *ipvs)
{
return ipvs->sysctl_sync_qlen_max;
@@ -1139,6 +1145,11 @@ static inline int sysctl_sync_ports(struct netns_ipvs *ipvs)
return 1;
}
+static inline int sysctl_sync_persist_mode(struct netns_ipvs *ipvs)
+{
+ return 0;
+}
+
static inline unsigned long sysctl_sync_qlen_max(struct netns_ipvs *ipvs)
{
return IPVS_SYNC_QLEN_MAX;
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 1b14abb..0c129cc 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -1715,6 +1715,12 @@ static struct ctl_table vs_vars[] = {
.proc_handler = &proc_do_sync_ports,
},
{
+ .procname = "sync_persist_mode",
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
+ {
.procname = "sync_qlen_max",
.maxlen = sizeof(unsigned long),
.mode = 0644,
@@ -3728,6 +3734,7 @@ static int __net_init ip_vs_control_net_init_sysctl(struct net *net)
tbl[idx++].data = &ipvs->sysctl_sync_ver;
ipvs->sysctl_sync_ports = 1;
tbl[idx++].data = &ipvs->sysctl_sync_ports;
+ tbl[idx++].data = &ipvs->sysctl_sync_persist_mode;
ipvs->sysctl_sync_qlen_max = nr_free_buffer_pages() / 32;
tbl[idx++].data = &ipvs->sysctl_sync_qlen_max;
ipvs->sysctl_sync_sock_size = 0;
diff --git a/net/netfilter/ipvs/ip_vs_sync.c b/net/netfilter/ipvs/ip_vs_sync.c
index 2fc6639..03c43c0 100644
--- a/net/netfilter/ipvs/ip_vs_sync.c
+++ b/net/netfilter/ipvs/ip_vs_sync.c
@@ -425,6 +425,16 @@ ip_vs_sync_buff_create_v0(struct netns_ipvs *ipvs)
return sb;
}
+/* Check if connection is controlled by persistence */
+static inline bool in_peristence(struct ip_vs_conn *cp)
+{
+ for (cp = cp->control; cp; cp = cp->control) {
+ if (cp->flags & IP_VS_CONN_F_TEMPLATE)
+ return true;
+ }
+ return false;
+}
+
/* Check if conn should be synced.
* pkts: conn packets, use sysctl_sync_threshold to avoid packet check
* - (1) sync_refresh_period: reduce sync rate. Additionally, retry
@@ -447,6 +457,8 @@ static int ip_vs_sync_conn_needed(struct netns_ipvs *ipvs,
/* Check if we sync in current state */
if (unlikely(cp->flags & IP_VS_CONN_F_TEMPLATE))
force = 0;
+ else if (unlikely(sysctl_sync_persist_mode(ipvs) && in_peristence(cp)))
+ return 0;
else if (likely(cp->protocol == IPPROTO_TCP)) {
if (!((1 << cp->state) &
((1 << IP_VS_TCP_S_ESTABLISHED) |
--
1.7.3.4
Regards
--
Julian Anastasov <ja@xxxxxx>
--
To unsubscribe from this list: send the line "unsubscribe lvs-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
