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MEDIUM: server: allow to remove servers at runtime except non purgeable

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Relax the condition on "delete server" CLI handler to be able to remove
all servers, even non dynamic, except if they are flagged as non
purgeable.

This change is necessary to extend the use cases for dynamic servers
with reload. It's expected that each dynamic server created via the CLI
is manually commited in the haproxy configuration by the user. Dynamic
servers will be present on reload only if they are present in the
configuration file. This means that non-dynamic servers must be allowed
to be removable at runtime.

The dynamic servers removal reg-test has been updated and renamed to
reflect its purpose. A new test is present to check that non-purgeable
servers cannot be removed.
This commit is contained in:
Amaury Denoyelle 2021-08-23 14:10:51 +02:00
parent 86f3707d14
commit 14c3c5c121
5 changed files with 155 additions and 56 deletions
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14
doc/management.txt
View File

@ -1470,6 +1470,11 @@ add server <backend>/<server> [args]*
init-addr method. This means that no resolution will be undertaken if a FQDN
is specified as an address, even if the server creation will be validated.
To support the reload operations, it is expected that the server created via
the CLI is also manually inserted in the relevant haproxy configuration file.
A dynamic server not present in the configuration won't be restored after a
reload operation.
A dynamic server may use the "track" keyword to follow the check status of
another server from the configuration. However, it is not possible to track
another dynamic server. This is to ensure that the tracking chain is kept
@ -1786,10 +1791,11 @@ del ssl crt-list <filename> <certfile[:line]>
numbers, use "show ssl crt-list -n <crtlist>".
del server <backend>/<server>
Remove a server attached to the backend <backend>. Only valid on a server
added at runtime. The server must be put in maintenance mode prior to its
deletion. The operation is cancelled if the serveur still has active
or idle connection or its connection queue is not empty.
Remove a server attached to the backend <backend>. All servers are eligible,
except servers which are referenced by other configuration elements. The
server must be put in maintenance mode prior to its deletion. The operation
is cancelled if the serveur still has active or idle connection or its
connection queue is not empty.
disable agent <backend>/<server>
Mark the auxiliary agent check as temporarily stopped.

98
reg-tests/server/cli_delete_dynamic_server.vtc Normal file
View File

@ -0,0 +1,98 @@
# This script is to test the proper behavior with dynamic servers insertion and
# deletion, in particular with the load-balancing of requests.
#
varnishtest "Delete server via cli"
feature ignore_unknown_macro
#REQUIRE_VERSION=2.4
# static server
server s1 -repeat 3 {
rxreq
txresp \
-body "resp from s1"
} -start
# use as a dynamic server, added then deleted via CLI
server s2 -repeat 3 {
rxreq
txresp \
-body "resp from s2"
} -start
haproxy h1 -conf {
defaults
mode http
timeout connect 1s
timeout client 1s
timeout server 1s
frontend fe
bind "fd@${feS}"
default_backend test
backend test
server s1 ${s1_addr}:${s1_port}
} -start
# add a new dynamic server to be able to delete it then
haproxy h1 -cli {
# add a dynamic server and enable it
send "experimental-mode on; add server test/s2 ${s2_addr}:${s2_port}"
expect ~ "New server registered."
send "enable server test/s2"
expect ~ ".*"
}
haproxy h1 -cli {
# experimental mode disabled
send "del server test/s1"
expect ~ "This command is restricted to experimental mode only."
# non existent backend
send "experimental-mode on; del server foo/s1"
expect ~ "No such backend."
# non existent server
send "experimental-mode on; del server test/other"
expect ~ "No such server."
}
# first check that both servers are active
client c1 -connect ${h1_feS_sock} {
txreq
rxresp
expect resp.body == "resp from s1"
txreq
rxresp
expect resp.body == "resp from s2"
} -run
# delete the dynamic server
haproxy h1 -cli {
# server not in maintenance mode
send "experimental-mode on; del server test/s2"
expect ~ "Only servers in maintenance mode can be deleted."
send "disable server test/s2"
expect ~ ".*"
# valid command
send "experimental-mode on; del server test/s2"
expect ~ "Server deleted."
}
# now check that only the first server is used
client c2 -connect ${h1_feS_sock} {
txreq
rxresp
expect resp.body == "resp from s1"
txreq
rxresp
expect resp.body == "resp from s1"
} -run

81
reg-tests/server/cli_delete_server.vtc
View File

@ -1,24 +1,21 @@
# This script is to test the ability to remove servers, unless they are
# referenced by some elements from the configuration.
#
varnishtest "Delete server via cli"
feature ignore_unknown_macro
#REQUIRE_VERSION=2.4
# static server
server s1 -repeat 3 {
server s1 {
rxreq
txresp \
-body "resp from s1"
} -start
# use as a dynamic server, added then deleted via CLI
server s2 -repeat 3 {
rxreq
txresp \
-body "resp from s2"
txresp
} -start
haproxy h1 -conf {
global
lua-load ${testdir}/get_srv_stats.lua
defaults
mode http
timeout connect 1s
@ -27,22 +24,19 @@ haproxy h1 -conf {
frontend fe
bind "fd@${feS}"
acl s1_full srv_sess_rate(test/s1) gt 50
default_backend test
backend test
server s1 ${s1_addr}:${s1_port}
http-request add-header s4-stats %[lua.get_srv_stats(s4)]
use-server s3 unless { always_false }
server s1 ${s1_addr}:${s1_port} # referenced in ACL
server s2 ${s1_addr}:${s1_port} check # referenced in track
server s3 ${s1_addr}:${s1_port} track s2 # referenced in use-server
server s4 ${s1_addr}:${s1_port} # referenced in lua script
server s5 ${s1_addr}:${s1_port} # removable server
} -start
# add a new dynamic server to be able to delete it then
haproxy h1 -cli {
# add a dynamic server and enable it
send "experimental-mode on; add server test/s2 ${s2_addr}:${s2_port}"
expect ~ "New server registered."
send "enable server test/s2"
expect ~ ".*"
}
haproxy h1 -cli {
# experimental mode disabled
send "del server test/s1"
@ -56,44 +50,37 @@ haproxy h1 -cli {
send "experimental-mode on; del server test/other"
expect ~ "No such server."
# static server
# server referenced in ACL
send "experimental-mode on; del server test/s1"
expect ~ "Only servers added at runtime via <add server> CLI cmd can be deleted."
expect ~ "This server cannot be removed at runtime due to other configuration elements pointing to it."
# tracked server
send "experimental-mode on; del server test/s2"
expect ~ "This server cannot be removed at runtime due to other configuration elements pointing to it."
# tracked server
send "experimental-mode on; del server test/s3"
expect ~ "This server cannot be removed at runtime due to other configuration elements pointing to it."
}
# first check that both servers are active
# make a request to force the execution of the lua script which references a
# server
client c1 -connect ${h1_feS_sock} {
txreq
rxresp
expect resp.body == "resp from s1"
txreq
rxresp
expect resp.body == "resp from s2"
} -run
# delete the dynamic server
haproxy h1 -cli {
# server not in maintenance mode
send "experimental-mode on; del server test/s2"
send "experimental-mode on; del server test/s4"
expect ~ "This server cannot be removed at runtime due to other configuration elements pointing to it."
send "experimental-mode on; del server test/s5"
expect ~ "Only servers in maintenance mode can be deleted."
send "disable server test/s2"
send "disable server test/s5"
expect ~ ".*"
# valid command
send "experimental-mode on; del server test/s2"
send "experimental-mode on; del server test/s5"
expect ~ "Server deleted."
}
# now check that only the first server is used
client c2 -connect ${h1_feS_sock} {
txreq
rxresp
expect resp.body == "resp from s1"
txreq
rxresp
expect resp.body == "resp from s1"
} -run

11
reg-tests/server/get_srv_stats.lua Normal file
View File

@ -0,0 +1,11 @@
local function lua_get_srv_stats(txn, name)
for _, backend in pairs(core.backends) do
for _, server in pairs(backend.servers) do
if server.name == name then
return server:get_stats()
end
end
end
end
core.register_fetches('get_srv_stats', lua_get_srv_stats)

7
src/server.c
View File

@ -4741,14 +4741,11 @@ static int cli_parse_delete_server(char **args, char *payload, struct appctx *ap
goto out;
}
if (!(srv->flags & SRV_F_DYNAMIC)) {
cli_err(appctx, "Only servers added at runtime via <add server> CLI cmd can be deleted.");
if (srv->flags & SRV_F_NON_PURGEABLE) {
cli_err(appctx, "This server cannot be removed at runtime due to other configuration elements pointing to it.");
goto out;
}
/* A dynamic server cannot be tracked. */
BUG_ON(srv->trackers);
/* Only servers in maintenance can be deleted. This ensures that the
* server is not present anymore in the lb structures (through
* lbprm.set_server_status_down).