高可用软件Keepalived发布1.2.11。2014-01-28.上个版本是2014-01-04的1.2.10。修复了很多Bug,如内存泄露相关，以及更好的libnl的支持。
keepalived是一个类似于layer3, 4 & 5交换机制的软件，也就是我们平时说的第3层、第4层和第5层交换。Keepalived的作用是检测web服务器的状态，如果有一台web服务器死机，或工作出现故障，Keepalived将检测到，并将有故障的web服务器从系统中剔除，当web服务器工作正常后Keepalived自动将web服务 器加入到服务器群中，这些工作全部自动完成，不需要人工干涉，需要人工做的只是修复故障的web服务器。
Layer3,4&5工作在IP/TCP协议栈的IP层，TCP层，及应用层,原理分别如下：
完全改进：
2014-01-28
Release 1.2.11
* ipvs: make nlerr2syserr libnl dependent. nlerr2syserr()
is only used when libnl is present... simply reflect this in
libipvs.
* Fix libnl/libnl-3 logic in configure script.
This patch causes the configure script to prefer libnl-3 over
libnl(1). The configure script will first check for libnl-3 and
libnl-genl-3. If both are found, use them. If not, check for
libnl(1). This is useful when building on systems that have both
libnl-3 and libnl(1) installed. It also fixes some redundant
libraries in LIBS.
* libipvs: libnl-3 include fix.
* lib: extend command lib string parser.
Extend cmd_make_strvec to support quoted string as a single slot
and commented string at the end of parsed string.
* lib: cosmetics at command.c.
Extend command framework to support logger and remove some dead
code. some cosmetics too.
* lib: extend vty to support logger.
* autoconf: better libnl3 detection.
* Fix memory allocation in parser. The set_value function was
incorrectly using sizeof (char *) when allocation and reallocating
memory.
* Fix memory allocation for MD5 digest.
The vrrp_in_chk_ipsecah and vrrp_build_ipsecah functions were
incorrectly using sizeof (unsigned char *) when allocating memory
for the MD5 digest.
* Fix memory leak in vty_read_config. If vty_use_backup_config
returns NULL, free any memory that has been allocated before
returning.
* Fix memory leak in check_include. The check_include function
should always free the allocated strvec.
* Check content length before allocating memory.
Since extract_content_length should return 0 if CONTENT_LENGTH is
not found in the buffer, this check should be done before
allocating memory. This avoids unnecessary malloc/free calls and
fixes a potential memory leak.
* Free memory if realloc fails in vty_out. If realloc returns NULL,
free the original memory before returning.
* Remove redundant close from vty_use_backup_config. The sav file
descriptor is closed after read, so there is no need to close it
again is chmod operation fails.
* Remove unnecessary netlink rtattr structures.
Both netlink_link_setmode and netlink_link_add_vmac have rtattr
structures that are no needed. The addattr_l function will handle
adding the rtattr to the message. Also, this patch removes
incorrect void pointer arithmetic when setting rta_len.
* vrrp: dont try to leave mcast group in unicast mode.
* vrrp: Release and refresh properly fd hash index.
Rehashing into the same loop as releasing is not really the best
idea... Reworked a little previous patch to properly release hash
entries related to the same instance and then hash it back on new
fd.
* vrrp: use configuration mcast group for leave message.
* vrrp: dont try to load ip_vs module when not needed.
下载：http://keepalived.org/software/keepalived-1.2.11.tar.gz
来自:开源中国社区
