In the process of breaking links between dns_* functions and other
structures (mainly server and a bit of resolution), the function
dns_get_ip_from_response needs to be reworked: it now can call
"callback" functions based on resolution's owner type to allow modifying
the way the response is processed.
For now, main purpose of the callback function is to check that an IP
address is not already affected to an element of the same type.
For now, only server type has a callback.
This patch introduces a some re-organisation around the DNS code in
HAProxy.
1. make the dns_* functions less dependent on 'struct server' and 'struct resolution'.
With this in mind, the following changes were performed:
- 'struct dns_options' has been removed from 'struct resolution' (well,
we might need it back at some point later, we'll see)
==> we'll use the 'struct dns_options' from the owner of the resolution
- dns_get_ip_from_response(): takes a 'struct dns_options' instead of
'struct resolution'
==> so the caller can pass its own dns options to get the most
appropriate IP from the response
- dns_process_resolve(): struct dns_option is deduced from new
resolution->requester_type parameter
2. add hostname_dn and hostname_dn_len into struct server
In order to avoid recomputing a server's hostname into its domain name
format (and use a trash buffer to store the result), it is safer to
compute it once at configuration parsing and to store it into the struct
server.
In the mean time, the struct resolution linked to the server doesn't
need anymore to store the hostname in domain name format. A simple
pointer to the server one will make the trick.
The function srv_alloc_dns_resolution() properly manages everything for
us: memory allocation, pointer updates, etc...
3. move resolvers pointer into struct server
This patch makes the pointer to struct dns_resolvers from struct
dns_resolution obsolete.
Purpose is to make the resolution as "neutral" as possible and since the
requester is already linked to the resolvers, then we don't need this
information anymore in the resolution itself.
A couple of new functions to allocate and free memory for a DNS
resolution structure. Main purpose is to to make the code related to DNS
more consistent.
They allocate or free memory for the structure itself. Later, if needed,
they should also allocate / free the buffers, etc, used by this structure.
They don't set/unset any parameters, this is the role of the caller.
This patch also implement calls to these function eveywhere it is
required.
This patch adds a new stats socket command to modify server
FQDNs at run time.
Its syntax:
set server <backend>/<server> fqdn <FQDN>
This patch also adds FQDNs to server state file at the end
of each line for backward compatibility ("-" if not present).
This patch adds server_template_init() function used to initialize servers
from server templates. It is called just after having parsed a 'server-template'
line.
This patch makes backend sections support 'server-template' new keyword.
Such 'server-template' objects are parsed similarly to a 'server' object
by parse_server() function, but its first arguments are as follows:
server-template <ID prefix> <nb | range> <ip | fqdn>:<port> ...
The remaining arguments are the same as for 'server' lines.
With such server template declarations, servers may be allocated with IDs
built from <ID prefix> and <nb | range> arguments.
For instance declaring:
server-template foo 1-5 google.com:80 ...
or
server-template foo 5 google.com:80 ...
would be equivalent to declare:
server foo1 google.com:80 ...
server foo2 google.com:80 ...
server foo3 google.com:80 ...
server foo4 google.com:80 ...
server foo5 google.com:80 ...
This patch moves the code which is responsible of finalizing server initializations
after having fully parsed a 'server' line (health-check, agent check and SNI expression
initializations) from parse_server() to new functions.
This patch moves the code responsible of copying default server settings
to a new server instance from parse_server() function to new defsrv_*_cpy()
functions which may be used both during server lines parsing and during server
templates initializations to come.
These defsrv_*_cpy() do not make any reference to anything else than default
server settings.
'resolvers' setting was not duplicated from default server setting to
new server instances when parsing 'server' lines.
This fix is simple: strdup() default resolvers <id> string argument after
having allocated a new server when parsing 'server' lines.
This patch must be backported to 1.7 and 1.6.
In server_parse_sni_expr(), we use the "proxy" global variable, when we
should probably be using "px" given as an argument.
It happens to work by accident right now, but may not in the future.
[wt: better backport it]
Any valid keyword could not be parsed anymore if provided after 'source' keyword.
This was due to the fact that 'source' number of arguments is variable.
So, as its parser srv_parse_source() is the only one who may know how many arguments
was provided after 'source' keyword, it updates 'cur_arg' variable (the index
in the line of the current arg to be parsed), this is a good thing.
This variable is also incremented by one (to skip the 'source' keyword).
This patch disable this behavior.
Should have come with dba9707 commit.
'usesrc' setting is not permitted on 'server' lines if not provided after
'source' setting. This is now also the case on 'default-server' lines.
Without this patch parse_server() parser displayed that 'usersrc' is
an unknown keyword.
Should have come with dba9707 commit.
This reverts commit 266b1a8 ("MEDIUM: server: Inherit CLI weight changes and
agent-check weight responses") from Michal Idzikowski, which is still broken.
It stops propagating weights at the first error encountered, leaving servers
in a random state depending on what LB algorithms are used on other servers
tracking the one experiencing the weight change. It's unsure what the best
way to address this is, but we cannot leave the servers in an inconsistent
state between farms. For example :
backend site1
mode http
balance uri
hash-type consistent
server s1 127.0.0.1:8001 weight 10 track servers/s1
backend site2
mode http
balance uri
server s1 127.0.0.1:8001 weight 10 track servers/s1
backend site3
mode http
balance uri
hash-type consistent
server s1 127.0.0.1:8001 weight 10 track servers/s1
backend servers
server s1 127.0.0.1:8001 weight 10 check inter 1s
The weight change is applied on "servers/s1". It tries to propagate
to the servers tracking it, which are site1/s1, site2/s1 and site3/s1.
Let's say that "weight 50%" is requested. The servers are linked in
reverse-order, so the change is applied to "servers/s1", then to
"site3/s1", then to "site2/s1" and this one fails and rejects the
change. The change is aborted and never propagated to "site1/s1",
which keeps the server in a different state from "site3/s1". At the
very least, in case of error, the changes should probably be unrolled.
Also the error reported on the CLI (when changing from the CLI) simply says :
Backend is using a static LB algorithm and only accepts weights '0%' and '100%'.
Without more indications what the faulty backend is.
Let's revert this change for now, as initially feared it will definitely
cause more harm than good and at least needs to be revisited. It was never
backported to any stable branch so no backport is needed.
When agent-check or CLI command executes relative weight change this patch
propagates it to tracking server allowing grouping many backends running on
same server underneath. Additionaly in case with many src IPs many backends
can have shared state checker, so there won't be unnecessary health checks.
[wt: Note: this will induce some behaviour change on some setups]
IP*_BINDANY is not defined under this system thus it is
necessary to make those fields access since CONFIG_HAP_TRANSPARENT
is not defined.
[wt: problem introduced late in 1.8-dev. The same fix was also reported
by Steven Davidovitz]
Each time we generate a dynamic cookie, we try to make sure the same
cookie hasn't been generated for another server, it's very unlikely, but
it may happen.
We only have to check that for the servers in the same proxy, no, need to
check in others, plus the code was buggy and would always check in the
first proxy of the proxy list.
This patch fixes a bug which came with 5e57643 commit where server
default CRT filenames were initialized to the same value as server
default CRL filenames.
This patch adds 'no-agent-check' setting supported both by 'default-server'
and 'server' directives to disable an agent check for a specific server which would
have 'agent-check' set as default value (inherited from 'default-server'
'agent-check' setting), or, on 'default-server' lines, to disable 'agent-check' setting
as default value for any further 'server' declarations.
For instance, provided this configuration:
default-server agent-check
server srv1
server srv2 no-agent-check
server srv3
default-server no-agent-check
server srv4
srv1 and srv3 would have an agent check enabled contrary to srv2 and srv4.
We do not allocate anymore anything when parsing 'default-server' 'agent-check'
setting.
Before this patch, only 'server' directives could support 'disabled' setting.
This patch makes also 'default-server' directives support this setting.
It is used to disable a list of servers declared after a 'defaut-server' directive.
'enabled' new keyword has been added, both supported as 'default-server' and
'server' setting, to enable again a list of servers (so, declared after a
'default-server enabled' directive) or to explicitly enable a specific server declared
after a 'default-server disabled' directive.
For instance provided this configuration:
default-server disabled
server srv1...
server srv2...
server srv3... enabled
server srv4... enabled
srv1 and srv2 are disabled and srv3 and srv4 enabled.
This is equivalent to this configuration:
default-server disabled
server srv1...
server srv2...
default-server enabled
server srv3...
server srv4...
even if it would have been preferable/shorter to declare:
server srv3...
server srv4...
default-server disabled
server srv1...
server srv2...
as 'enabled' is the default server state.
This patch makes 'default-server' support 'addr' setting.
The code which was responsible of parsing 'server' 'addr' setting
has moved from parse_server() to implement a new parser
callable both as 'default-server' and 'server' 'addr' setting parser.
Should not break anything.
This patch makes 'default-server' directives support 'sni' settings.
A field 'sni_expr' has been added to 'struct server' to temporary
stores SNI expressions as strings during both 'default-server' and 'server'
lines parsing. So, to duplicate SNI expressions from 'default-server' 'sni' setting
for new 'server' instances we only have to "strdup" these strings as this is
often done for most of the 'server' settings.
Then, sample expressions are computed calling sample_parse_expr() (only for 'server'
instances).
A new function has been added to produce the same error output as before in case
of any error during 'sni' settings parsing (display_parser_err()).
Should not break anything.
Before this patch, only 'server' directives could support 'source' setting.
This patch makes also 'default-server' directives support this setting.
To do so, we had to extract the code responsible of parsing 'source' setting
arguments from parse_server() function and make it callable both
as 'default-server' and 'server' 'source' setting parser. So, the code is mostly
the same as before except that before allocating anything for 'struct conn_src'
members, we must free the memory previously allocated.
Should not break anything.
Before this patch, 'cookie' setting was only supported by 'server' directives.
This patch makes 'default-server' directive also support 'cookie' setting.
Should not break anything.
Before this path, 'observe' setting was only supported by 'server' directives.
This patch makes 'default-server' directives also support 'observe' setting.
Should not break anything.
Before this patch only 'server' directives could support 'redir' setting.
This patch makes also 'default-server' directives support 'redir' setting.
Should not break anything.
Before this patch only 'server' directives could support 'track' setting.
This patch makes 'default-server' directives also support this setting.
Should not break anything.
Before this patch 'check' setting was only supported by 'server' directives.
This patch makes also 'default-server' directives support this setting.
A new 'no-check' keyword parser has been implemented to disable this setting both
in 'default-server' and 'server' directives.
Should not break anything.
This patch makes 'default-server' directive support 'verifyhost' setting.
Note: there was a little memory leak when several 'verifyhost' arguments were
supplied on the same 'server' line.
This patch makes 'default-server' directive support 'send-proxy'
(resp. 'send-proxy-v2') setting.
A new keyword 'no-send-proxy' (resp. 'no-send-proxy-v2') has been added
to disable 'send-proxy' (resp. 'send-proxy-v2') setting both in 'server' and
'default-server' directives.
This patch makes 'default-server' directive support 'non-stick' setting.
A new keyword 'stick' has been added so that to disable
'non-stick' setting both in 'server' and 'default-server' directives.
This patch makes 'default-server' directive support 'check-send-proxy' setting.
A new keyword 'no-check-send-proxy' has been added so that to disable
'check-send-proxy' setting both in 'server' and 'default-server' directives.
At this time, only 'server' supported 'backup' keyword.
This patch makes also 'default-server' directive support this keyword.
A new keyword 'no-backup' has been added so that to disable 'backup' setting
both in 'server' and 'default-server' directives.
For instance, provided the following sequence of directives:
default-server backup
server srv1
server srv2 no-backup
default-server no-backup
server srv3
server srv4 backup
srv1 and srv4 are declared as backup servers,
srv2 and srv3 are declared as non-backup servers.
There is no reason to emit such an error message:
"'default-server' expects <name> and <addr>[:<port>] as arguments."
if less than two arguments are provided on 'default-server' lines.
This is a 'server' specific error message.
This adds a new "dynamic" keyword for the cookie option. If set, a cookie
will be generated for each server (assuming one isn't already provided on
the "server" line), from the IP of the server, the TCP port, and a secret
key provided. To provide the secret key, a new keyword as been added,
"dynamic-cookie-key", for backends.
Example :
backend bk_web
balance roundrobin
dynamic-cookie-key "bla"
cookie WEBSRV insert dynamic
server s1 127.0.0.1:80 check
server s2 192.168.56.1:80 check
This is a first step to be able to dynamically add and remove servers,
without modifying the configuration file, and still have all the load
balancers redirect the traffic to the right server.
Provide a way to generate session cookies, based on the IP address of the
server, the TCP port, and a secret key provided.
This change adds possibility to change agent-addr and agent-send directives
by CLI/socket. Now you can replace server's and their configuration without
reloading/restarting whole haproxy, so it's a step in no-reload/no-restart
direction.
Depends on #e9602af - agent-addr is implemented there.
Can be backported to 1.7.
This directive add possibility to set different address for agent-checks.
With this you can manage server status and weight from central place.
Can be backported to 1.7.
When a server doesn't resolve we don't know the address family so we
can't perform the basic protocol validations. However we know that we'll
ultimately resolve to AF_INET4 or AF_INET6 so the controls are OK. It is
important to proceed like this otherwise it will not be possible to start
with unresolved addresses.
Next patch will cause the port to disappear from the address field when servers
do not resolve so we need to take it from the separate field provided by
str2sa_range().
