3. Global parameters -------------------- Parameters in the "global" section are process-wide and often OS-specific. They are generally set once for all and do not need being changed once correct. Some of them have command-line equivalents. The following keywords are supported in the "global" section : * Process management and security - ca-base - chroot - crt-base - daemon - gid - group - log - log-send-hostname - nbproc - pidfile - uid - ulimit-n - user - stats - ssl-server-verify - node - description - unix-bind * Performance tuning - max-spread-checks - maxconn - maxconnrate - maxcomprate - maxcompcpuusage - maxpipes - maxsessrate - maxsslconn - maxsslrate - noepoll - nokqueue - nopoll - nosplice - nogetaddrinfo - spread-checks - tune.bufsize - tune.chksize - tune.comp.maxlevel - tune.http.cookielen - tune.http.maxhdr - tune.idletimer - tune.maxaccept - tune.maxpollevents - tune.maxrewrite - tune.pipesize - tune.rcvbuf.client - tune.rcvbuf.server - tune.sndbuf.client - tune.sndbuf.server - tune.ssl.cachesize - tune.ssl.lifetime - tune.ssl.force-private-cache - tune.ssl.maxrecord - tune.ssl.default-dh-param - tune.zlib.memlevel - tune.zlib.windowsize * Debugging - debug - quiet 3.1. Process management and security ------------------------------------ ca-base <dir> Assigns a default directory to fetch SSL CA certificates and CRLs from when a relative path is used with "ca-file" or "crl-file" directives. Absolute locations specified in "ca-file" and "crl-file" prevail and ignore "ca-base". chroot <jail dir> Changes current directory to <jail dir> and performs a chroot() there before dropping privileges. This increases the security level in case an unknown vulnerability would be exploited, since it would make it very hard for the attacker to exploit the system. This only works when the process is started with superuser privileges. It is important to ensure that <jail_dir> is both empty and unwritable to anyone. cpu-map <"all"|"odd"|"even"|process_num> <cpu-set>... On Linux 2.6 and above, it is possible to bind a process to a specific CPU set. This means that the process will never run on other CPUs. The "cpu-map" directive specifies CPU sets for process sets. The first argument is the process number to bind. This process must have a number between 1 and 32 or 64, depending on the machine's word size, and any process IDs above nbproc are ignored. It is possible to specify all processes at once using "all", only odd numbers using "odd" or even numbers using "even", just like with the "bind-process" directive. The second and forthcoming arguments are CPU sets. Each CPU set is either a unique number between 0 and 31 or 63 or a range with two such numbers delimited by a dash ('-'). Multiple CPU numbers or ranges may be specified, and the processes will be allowed to bind to all of them. Obviously, multiple "cpu-map" directives may be specified. Each "cpu-map" directive will replace the previous ones when they overlap. crt-base <dir> Assigns a default directory to fetch SSL certificates from when a relative path is used with "crtfile" directives. Absolute locations specified after "crtfile" prevail and ignore "crt-base". daemon Makes the process fork into background. This is the recommended mode of operation. It is equivalent to the command line "-D" argument. It can be disabled by the command line "-db" argument. gid <number> Changes the process' group ID to <number>. It is recommended that the group ID is dedicated to HAProxy or to a small set of similar daemons. HAProxy must be started with a user belonging to this group, or with superuser privileges. Note that if haproxy is started from a user having supplementary groups, it will only be able to drop these groups if started with superuser privileges. See also "group" and "uid". group <group name> Similar to "gid" but uses the GID of group name <group name> from /etc/group. See also "gid" and "user". log <address> [len <length>] <facility> [max level [min level]] Adds a global syslog server. Up to two global servers can be defined. They will receive logs for startups and exits, as well as all logs from proxies configured with "log global". <address> can be one of: - An IPv4 address optionally followed by a colon and a UDP port. If no port is specified, 514 is used by default (the standard syslog port). - An IPv6 address followed by a colon and optionally a UDP port. If no port is specified, 514 is used by default (the standard syslog port). - A filesystem path to a UNIX domain socket, keeping in mind considerations for chroot (be sure the path is accessible inside the chroot) and uid/gid (be sure the path is appropriately writeable). Any part of the address string may reference any number of environment variables by preceding their name with a dollar sign ('$') and optionally enclosing them with braces ('{}'), similarly to what is done in Bourne shell. <length> is an optional maximum line length. Log lines larger than this value will be truncated before being sent. The reason is that syslog servers act differently on log line length. All servers support the default value of 1024, but some servers simply drop larger lines while others do log them. If a server supports long lines, it may make sense to set this value here in order to avoid truncating long lines. Similarly, if a server drops long lines, it is preferable to truncate them before sending them. Accepted values are 80 to 65535 inclusive. The default value of 1024 is generally fine for all standard usages. Some specific cases of long captures or JSON-formated logs may require larger values. <facility> must be one of the 24 standard syslog facilities : kern user mail daemon auth syslog lpr news uucp cron auth2 ftp ntp audit alert cron2 local0 local1 local2 local3 local4 local5 local6 local7 An optional level can be specified to filter outgoing messages. By default, all messages are sent. If a maximum level is specified, only messages with a severity at least as important as this level will be sent. An optional minimum level can be specified. If it is set, logs emitted with a more severe level than this one will be capped to this level. This is used to avoid sending "emerg" messages on all terminals on some default syslog configurations. Eight levels are known : emerg alert crit err warning notice info debug log-send-hostname [<string>] Sets the hostname field in the syslog header. If optional "string" parameter is set the header is set to the string contents, otherwise uses the hostname of the system. Generally used if one is not relaying logs through an intermediate syslog server or for simply customizing the hostname printed in the logs. log-tag <string> Sets the tag field in the syslog header to this string. It defaults to the program name as launched from the command line, which usually is "haproxy". Sometimes it can be useful to differentiate between multiple processes running on the same host. nbproc <number> Creates <number> processes when going daemon. This requires the "daemon" mode. By default, only one process is created, which is the recommended mode of operation. For systems limited to small sets of file descriptors per process, it may be needed to fork multiple daemons. USING MULTIPLE PROCESSES IS HARDER TO DEBUG AND IS REALLY DISCOURAGED. See also "daemon". pidfile <pidfile> Writes pids of all daemons into file <pidfile>. This option is equivalent to the "-p" command line argument. The file must be accessible to the user starting the process. See also "daemon". stats bind-process [ all | odd | even | <number 1-64>[-<number 1-64>] ] ... Limits the stats socket to a certain set of processes numbers. By default the stats socket is bound to all processes, causing a warning to be emitted when nbproc is greater than 1 because there is no way to select the target process when connecting. However, by using this setting, it becomes possible to pin the stats socket to a specific set of processes, typically the first one. The warning will automatically be disabled when this setting is used, whatever the number of processes used. The maximum process ID depends on the machine's word size (32 or 64). A better option consists in using the "process" setting of the "stats socket" line to force the process on each line. ssl-default-bind-ciphers <ciphers> This setting is only available when support for OpenSSL was built in. It sets the default string describing the list of cipher algorithms ("cipher suite") that are negotiated during the SSL/TLS handshake for all "bind" lines which do not explicitly define theirs. The format of the string is defined in "man 1 ciphers" from OpenSSL man pages, and can be for instance a string such as "AES:ALL:!aNULL:!eNULL:+RC4:@STRENGTH" (without quotes). Please check the "bind" keyword for more information. ssl-default-bind-options [<option>]... This setting is only available when support for OpenSSL was built in. It sets default ssl-options to force on all "bind" lines. Please check the "bind" keyword to see available options. Example: global ssl-default-bind-options no-sslv3 no-tls-tickets ssl-default-server-ciphers <ciphers> This setting is only available when support for OpenSSL was built in. It sets the default string describing the list of cipher algorithms that are negotiated during the SSL/TLS handshake with the server, for all "server" lines which do not explicitly define theirs. The format of the string is defined in "man 1 ciphers". Please check the "server" keyword for more information. ssl-default-server-options [<option>]... This setting is only available when support for OpenSSL was built in. It sets default ssl-options to force on all "server" lines. Please check the "server" keyword to see available options. ssl-server-verify [none|required] The default behavior for SSL verify on servers side. If specified to 'none', servers certificates are not verified. The default is 'required' except if forced using cmdline option '-dV'. stats socket [<address:port>|<path>] [param*] Binds a UNIX socket to <path> or a TCPv4/v6 address to <address:port>. Connections to this socket will return various statistics outputs and even allow some commands to be issued to change some runtime settings. Please consult section 9.2 "Unix Socket commands" for more details. All parameters supported by "bind" lines are supported, for instance to restrict access to some users or their access rights. Please consult section 5.1 for more information. stats timeout <timeout, in milliseconds> The default timeout on the stats socket is set to 10 seconds. It is possible to change this value with "stats timeout". The value must be passed in milliseconds, or be suffixed by a time unit among { us, ms, s, m, h, d }. stats maxconn <connections> By default, the stats socket is limited to 10 concurrent connections. It is possible to change this value with "stats maxconn". uid <number> Changes the process' user ID to <number>. It is recommended that the user ID is dedicated to HAProxy or to a small set of similar daemons. HAProxy must be started with superuser privileges in order to be able to switch to another one. See also "gid" and "user". ulimit-n <number> Sets the maximum number of per-process file-descriptors to <number>. By default, it is automatically computed, so it is recommended not to use this option. unix-bind [ prefix <prefix> ] [ mode <mode> ] [ user <user> ] [ uid <uid> ] [ group <group> ] [ gid <gid> ] Fixes common settings to UNIX listening sockets declared in "bind" statements. This is mainly used to simplify declaration of those UNIX sockets and reduce the risk of errors, since those settings are most commonly required but are also process-specific. The <prefix> setting can be used to force all socket path to be relative to that directory. This might be needed to access another component's chroot. Note that those paths are resolved before haproxy chroots itself, so they are absolute. The <mode>, <user>, <uid>, <group> and <gid> all have the same meaning as their homonyms used by the "bind" statement. If both are specified, the "bind" statement has priority, meaning that the "unix-bind" settings may be seen as process-wide default settings. user <user name> Similar to "uid" but uses the UID of user name <user name> from /etc/passwd. See also "uid" and "group". node <name> Only letters, digits, hyphen and underscore are allowed, like in DNS names. This statement is useful in HA configurations where two or more processes or servers share the same IP address. By setting a different node-name on all nodes, it becomes easy to immediately spot what server is handling the traffic. description <text> Add a text that describes the instance. Please note that it is required to escape certain characters (# for example) and this text is inserted into a html page so you should avoid using "<" and ">" characters. 3.2. Performance tuning ----------------------- max-spread-checks <delay in milliseconds> By default, haproxy tries to spread the start of health checks across the smallest health check interval of all the servers in a farm. The principle is to avoid hammering services running on the same server. But when using large check intervals (10 seconds or more), the last servers in the farm take some time before starting to be tested, which can be a problem. This parameter is used to enforce an upper bound on delay between the first and the last check, even if the servers' check intervals are larger. When servers run with shorter intervals, their intervals will be respected though. maxconn <number> Sets the maximum per-process number of concurrent connections to <number>. It is equivalent to the command-line argument "-n". Proxies will stop accepting connections when this limit is reached. The "ulimit-n" parameter is automatically adjusted according to this value. See also "ulimit-n". Note: the "select" poller cannot reliably use more than 1024 file descriptors on some platforms. If your platform only supports select and reports "select FAILED" on startup, you need to reduce maxconn until it works (slightly below 500 in general). maxconnrate <number> Sets the maximum per-process number of connections per second to <number>. Proxies will stop accepting connections when this limit is reached. It can be used to limit the global capacity regardless of each frontend capacity. It is important to note that this can only be used as a service protection measure, as there will not necessarily be a fair share between frontends when the limit is reached, so it's a good idea to also limit each frontend to some value close to its expected share. Also, lowering tune.maxaccept can improve fairness. maxcomprate <number> Sets the maximum per-process input compression rate to <number> kilobytes per second. For each session, if the maximum is reached, the compression level will be decreased during the session. If the maximum is reached at the beginning of a session, the session will not compress at all. If the maximum is not reached, the compression level will be increased up to tune.comp.maxlevel. A value of zero means there is no limit, this is the default value. maxcompcpuusage <number> Sets the maximum CPU usage HAProxy can reach before stopping the compression for new requests or decreasing the compression level of current requests. It works like 'maxcomprate' but measures CPU usage instead of incoming data bandwidth. The value is expressed in percent of the CPU used by haproxy. In case of multiple processes (nbproc > 1), each process manages its individual usage. A value of 100 disable the limit. The default value is 100. Setting a lower value will prevent the compression work from slowing the whole process down and from introducing high latencies. maxpipes <number> Sets the maximum per-process number of pipes to <number>. Currently, pipes are only used by kernel-based tcp splicing. Since a pipe contains two file descriptors, the "ulimit-n" value will be increased accordingly. The default value is maxconn/4, which seems to be more than enough for most heavy usages. The splice code dynamically allocates and releases pipes, and can fall back to standard copy, so setting this value too low may only impact performance. maxsessrate <number> Sets the maximum per-process number of sessions per second to <number>. Proxies will stop accepting connections when this limit is reached. It can be used to limit the global capacity regardless of each frontend capacity. It is important to note that this can only be used as a service protection measure, as there will not necessarily be a fair share between frontends when the limit is reached, so it's a good idea to also limit each frontend to some value close to its expected share. Also, lowering tune.maxaccept can improve fairness. maxsslconn <number> Sets the maximum per-process number of concurrent SSL connections to <number>. By default there is no SSL-specific limit, which means that the global maxconn setting will apply to all connections. Setting this limit avoids having openssl use too much memory and crash when malloc returns NULL (since it unfortunately does not reliably check for such conditions). Note that the limit applies both to incoming and outgoing connections, so one connection which is deciphered then ciphered accounts for 2 SSL connections. maxsslrate <number> Sets the maximum per-process number of SSL sessions per second to <number>. SSL listeners will stop accepting connections when this limit is reached. It can be used to limit the global SSL CPU usage regardless of each frontend capacity. It is important to note that this can only be used as a service protection measure, as there will not necessarily be a fair share between frontends when the limit is reached, so it's a good idea to also limit each frontend to some value close to its expected share. It is also important to note that the sessions are accounted before they enter the SSL stack and not after, which also protects the stack against bad handshakes. Also, lowering tune.maxaccept can improve fairness. maxzlibmem <number> Sets the maximum amount of RAM in megabytes per process usable by the zlib. When the maximum amount is reached, future sessions will not compress as long as RAM is unavailable. When sets to 0, there is no limit. The default value is 0. The value is available in bytes on the UNIX socket with "show info" on the line "MaxZlibMemUsage", the memory used by zlib is "ZlibMemUsage" in bytes. noepoll Disables the use of the "epoll" event polling system on Linux. It is equivalent to the command-line argument "-de". The next polling system used will generally be "poll". See also "nopoll". nokqueue Disables the use of the "kqueue" event polling system on BSD. It is equivalent to the command-line argument "-dk". The next polling system used will generally be "poll". See also "nopoll". nopoll Disables the use of the "poll" event polling system. It is equivalent to the command-line argument "-dp". The next polling system used will be "select". It should never be needed to disable "poll" since it's available on all platforms supported by HAProxy. See also "nokqueue" and "noepoll". nosplice Disables the use of kernel tcp splicing between sockets on Linux. It is equivalent to the command line argument "-dS". Data will then be copied using conventional and more portable recv/send calls. Kernel tcp splicing is limited to some very recent instances of kernel 2.6. Most versions between 2.6.25 and 2.6.28 are buggy and will forward corrupted data, so they must not be used. This option makes it easier to globally disable kernel splicing in case of doubt. See also "option splice-auto", "option splice-request" and "option splice-response". nogetaddrinfo Disables the use of getaddrinfo(3) for name resolving. It is equivalent to the command line argument "-dG". Deprecated gethostbyname(3) will be used. spread-checks <0..50, in percent> Sometimes it is desirable to avoid sending agent and health checks to servers at exact intervals, for instance when many logical servers are located on the same physical server. With the help of this parameter, it becomes possible to add some randomness in the check interval between 0 and +/- 50%. A value between 2 and 5 seems to show good results. The default value remains at 0. tune.bufsize <number> Sets the buffer size to this size (in bytes). Lower values allow more sessions to coexist in the same amount of RAM, and higher values allow some applications with very large cookies to work. The default value is 16384 and can be changed at build time. It is strongly recommended not to change this from the default value, as very low values will break some services such as statistics, and values larger than default size will increase memory usage, possibly causing the system to run out of memory. At least the global maxconn parameter should be decreased by the same factor as this one is increased. If HTTP request is larger than (tune.bufsize - tune.maxrewrite), haproxy will return HTTP 400 (Bad Request) error. Similarly if an HTTP response is larger than this size, haproxy will return HTTP 502 (Bad Gateway). tune.chksize <number> Sets the check buffer size to this size (in bytes). Higher values may help find string or regex patterns in very large pages, though doing so may imply more memory and CPU usage. The default value is 16384 and can be changed at build time. It is not recommended to change this value, but to use better checks whenever possible. tune.comp.maxlevel <number> Sets the maximum compression level. The compression level affects CPU usage during compression. This value affects CPU usage during compression. Each session using compression initializes the compression algorithm with this value. The default value is 1. tune.http.cookielen <number> Sets the maximum length of captured cookies. This is the maximum value that the "capture cookie xxx len yyy" will be allowed to take, and any upper value will automatically be truncated to this one. It is important not to set too high a value because all cookie captures still allocate this size whatever their configured value (they share a same pool). This value is per request per response, so the memory allocated is twice this value per connection. When not specified, the limit is set to 63 characters. It is recommended not to change this value. tune.http.maxhdr <number> Sets the maximum number of headers in a request. When a request comes with a number of headers greater than this value (including the first line), it is rejected with a "400 Bad Request" status code. Similarly, too large responses are blocked with "502 Bad Gateway". The default value is 101, which is enough for all usages, considering that the widely deployed Apache server uses the same limit. It can be useful to push this limit further to temporarily allow a buggy application to work by the time it gets fixed. Keep in mind that each new header consumes 32bits of memory for each session, so don't push this limit too high. tune.idletimer <timeout> Sets the duration after which haproxy will consider that an empty buffer is probably associated with an idle stream. This is used to optimally adjust some packet sizes while forwarding large and small data alternatively. The decision to use splice() or to send large buffers in SSL is modulated by this parameter. The value is in milliseconds between 0 and 65535. A value of zero means that haproxy will not try to detect idle streams. The default is 1000, which seems to correctly detect end user pauses (eg: read a page before clicking). There should be not reason for changing this value. Please check tune.ssl.maxrecord below. tune.maxaccept <number> Sets the maximum number of consecutive connections a process may accept in a row before switching to other work. In single process mode, higher numbers give better performance at high connection rates. However in multi-process modes, keeping a bit of fairness between processes generally is better to increase performance. This value applies individually to each listener, so that the number of processes a listener is bound to is taken into account. This value defaults to 64. In multi-process mode, it is divided by twice the number of processes the listener is bound to. Setting this value to -1 completely disables the limitation. It should normally not be needed to tweak this value. tune.maxpollevents <number> Sets the maximum amount of events that can be processed at once in a call to the polling system. The default value is adapted to the operating system. It has been noticed that reducing it below 200 tends to slightly decrease latency at the expense of network bandwidth, and increasing it above 200 tends to trade latency for slightly increased bandwidth. tune.maxrewrite <number> Sets the reserved buffer space to this size in bytes. The reserved space is used for header rewriting or appending. The first reads on sockets will never fill more than bufsize-maxrewrite. Historically it has defaulted to half of bufsize, though that does not make much sense since there are rarely large numbers of headers to add. Setting it too high prevents processing of large requests or responses. Setting it too low prevents addition of new headers to already large requests or to POST requests. It is generally wise to set it to about 1024. It is automatically readjusted to half of bufsize if it is larger than that. This means you don't have to worry about it when changing bufsize. tune.pipesize <number> Sets the kernel pipe buffer size to this size (in bytes). By default, pipes are the default size for the system. But sometimes when using TCP splicing, it can improve performance to increase pipe sizes, especially if it is suspected that pipes are not filled and that many calls to splice() are performed. This has an impact on the kernel's memory footprint, so this must not be changed if impacts are not understood. tune.rcvbuf.client <number> tune.rcvbuf.server <number> Forces the kernel socket receive buffer size on the client or the server side to the specified value in bytes. This value applies to all TCP/HTTP frontends and backends. It should normally never be set, and the default size (0) lets the kernel autotune this value depending on the amount of available memory. However it can sometimes help to set it to very low values (eg: 4096) in order to save kernel memory by preventing it from buffering too large amounts of received data. Lower values will significantly increase CPU usage though. tune.sndbuf.client <number> tune.sndbuf.server <number> Forces the kernel socket send buffer size on the client or the server side to the specified value in bytes. This value applies to all TCP/HTTP frontends and backends. It should normally never be set, and the default size (0) lets the kernel autotune this value depending on the amount of available memory. However it can sometimes help to set it to very low values (eg: 4096) in order to save kernel memory by preventing it from buffering too large amounts of received data. Lower values will significantly increase CPU usage though. Another use case is to prevent write timeouts with extremely slow clients due to the kernel waiting for a large part of the buffer to be read before notifying haproxy again. tune.ssl.cachesize <number> Sets the size of the global SSL session cache, in a number of blocks. A block is large enough to contain an encoded session without peer certificate. An encoded session with peer certificate is stored in multiple blocks depending on the size of the peer certificate. A block uses approximately 200 bytes of memory. The default value may be forced at build time, otherwise defaults to 20000. When the cache is full, the most idle entries are purged and reassigned. Higher values reduce the occurrence of such a purge, hence the number of CPU-intensive SSL handshakes by ensuring that all users keep their session as long as possible. All entries are pre-allocated upon startup and are shared between all processes if "nbproc" is greater than 1. Setting this value to 0 disables the SSL session cache. tune.ssl.force-private-cache This boolean disables SSL session cache sharing between all processes. It should normally not be used since it will force many renegotiations due to clients hitting a random process. But it may be required on some operating systems where none of the SSL cache synchronization method may be used. In this case, adding a first layer of hash-based load balancing before the SSL layer might limit the impact of the lack of session sharing. tune.ssl.lifetime <timeout> Sets how long a cached SSL session may remain valid. This time is expressed in seconds and defaults to 300 (5 min). It is important to understand that it does not guarantee that sessions will last that long, because if the cache is full, the longest idle sessions will be purged despite their configured lifetime. The real usefulness of this setting is to prevent sessions from being used for too long. tune.ssl.maxrecord <number> Sets the maximum amount of bytes passed to SSL_write() at a time. Default value 0 means there is no limit. Over SSL/TLS, the client can decipher the data only once it has received a full record. With large records, it means that clients might have to download up to 16kB of data before starting to process them. Limiting the value can improve page load times on browsers located over high latency or low bandwidth networks. It is suggested to find optimal values which fit into 1 or 2 TCP segments (generally 1448 bytes over Ethernet with TCP timestamps enabled, or 1460 when timestamps are disabled), keeping in mind that SSL/TLS add some overhead. Typical values of 1419 and 2859 gave good results during tests. Use "strace -e trace=write" to find the best value. Haproxy will automatically switch to this setting after an idle stream has been detected (see tune.idletimer above). tune.ssl.default-dh-param <number> Sets the maximum size of the Diffie-Hellman parameters used for generating the ephemeral/temporary Diffie-Hellman key in case of DHE key exchange. The final size will try to match the size of the server's RSA (or DSA) key (e.g, a 2048 bits temporary DH key for a 2048 bits RSA key), but will not exceed this maximum value. Default value if 1024. Only 1024 or higher values are allowed. Higher values will increase the CPU load, and values greater than 1024 bits are not supported by Java 7 and earlier clients. This value is not used if static Diffie-Hellman parameters are supplied via the certificate file. tune.zlib.memlevel <number> Sets the memLevel parameter in zlib initialization for each session. It defines how much memory should be allocated for the internal compression state. A value of 1 uses minimum memory but is slow and reduces compression ratio, a value of 9 uses maximum memory for optimal speed. Can be a value between 1 and 9. The default value is 8. tune.zlib.windowsize <number> Sets the window size (the size of the history buffer) as a parameter of the zlib initialization for each session. Larger values of this parameter result in better compression at the expense of memory usage. Can be a value between 8 and 15. The default value is 15. 3.3. Debugging -------------- debug Enables debug mode which dumps to stdout all exchanges, and disables forking into background. It is the equivalent of the command-line argument "-d". It should never be used in a production configuration since it may prevent full system startup. quiet Do not display any message during startup. It is equivalent to the command- line argument "-q". 3.4. Userlists -------------- It is possible to control access to frontend/backend/listen sections or to http stats by allowing only authenticated and authorized users. To do this, it is required to create at least one userlist and to define users. userlist <listname> Creates new userlist with name <listname>. Many independent userlists can be used to store authentication &authorization data for independent customers. group <groupname> [users <user>,<user>,(...)] Adds group <groupname> to the current userlist. It is also possible to attach users to this group by using a comma separated list of names proceeded by "users" keyword. user <username> [password|insecure-password <password>] [groups <group>,<group>,(...)] Adds user <username> to the current userlist. Both secure (encrypted) and insecure (unencrypted) passwords can be used. Encrypted passwords are evaluated using the crypt(3) function so depending of the system's capabilities, different algorithms are supported. For example modern Glibc based Linux system supports MD5, SHA-256, SHA-512 and of course classic, DES-based method of encrypting passwords. Example: userlist L1 group G1 users tiger,scott group G2 users xdb,scott user tiger password $6$k6y3o.eP$JlKBx9za9667qe4(...)xHSwRv6J.C0/D7cV91 user scott insecure-password elgato user xdb insecure-password hello userlist L2 group G1 group G2 user tiger password $6$k6y3o.eP$JlKBx(...)xHSwRv6J.C0/D7cV91 groups G1 user scott insecure-password elgato groups G1,G2 user xdb insecure-password hello groups G2 Please note that both lists are functionally identical. 3.5. Peers ---------- It is possible to synchronize server entries in stick tables between several haproxy instances over TCP connections in a multi-master fashion. Each instance pushes its local updates and insertions to remote peers. Server IDs are used to identify servers remotely, so it is important that configurations look similar or at least that the same IDs are forced on each server on all participants. Interrupted exchanges are automatically detected and recovered from the last known point. In addition, during a soft restart, the old process connects to the new one using such a TCP connection to push all its entries before the new process tries to connect to other peers. That ensures very fast replication during a reload, it typically takes a fraction of a second even for large tables. peers <peersect> Creates a new peer list with name <peersect>. It is an independent section, which is referenced by one or more stick-tables. disabled Disables a peers section. It disables both listening and any synchronization related to this section. This is provided to disable synchronization of stick tables without having to comment out all "peers" references. enable This re-enables a disabled peers section which was previously disabled. peer <peername> <ip>:<port> Defines a peer inside a peers section. If <peername> is set to the local peer name (by default hostname, or forced using "-L" command line option), haproxy will listen for incoming remote peer connection on <ip>:<port>. Otherwise, <ip>:<port> defines where to connect to to join the remote peer, and <peername> is used at the protocol level to identify and validate the remote peer on the server side. During a soft restart, local peer <ip>:<port> is used by the old instance to connect the new one and initiate a complete replication (teaching process). It is strongly recommended to have the exact same peers declaration on all peers and to only rely on the "-L" command line argument to change the local peer name. This makes it easier to maintain coherent configuration files across all peers. Any part of the address string may reference any number of environment variables by preceding their name with a dollar sign ('$') and optionally enclosing them with braces ('{}'), similarly to what is done in Bourne shell. Example: peers mypeers peer haproxy1 192.168.0.1:1024 peer haproxy2 192.168.0.2:1024 peer haproxy3 10.2.0.1:1024 backend mybackend mode tcp balance roundrobin stick-table type ip size 20k peers mypeers stick on src server srv1 192.168.0.30:80 server srv2 192.168.0.31:80