Mercurial > hg > nginx-site

comparison xml/en/docs/http/ngx_http_upstream_module.xml @ 968:fa19bacf6e1e

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Unified upstream server up/down state terminology. The "down" word is reserved for usage with the flag of the same name, that marks server as permanently unavailable.
author Vladimir Homutov <vl@nginx.com>
date Thu, 15 Aug 2013 15:54:23 +0400
parents 95c3c3bbf1ce
children 7c542520b8f7
comparison
equal deleted inserted replaced
967:81717ad0a9c9 968:fa19bacf6e1e
8 <!DOCTYPE module SYSTEM "../../../../dtd/module.dtd"> 8 <!DOCTYPE module SYSTEM "../../../../dtd/module.dtd">
9 9
10 <module name="Module ngx_http_upstream_module" 10 <module name="Module ngx_http_upstream_module"
11 link="/en/docs/http/ngx_http_upstream_module.html" 11 link="/en/docs/http/ngx_http_upstream_module.html"
12 lang="en" 12 lang="en"
13 rev="7"> 13 rev="8">
14 14
15 <section id="summary"> 15 <section id="summary">
16 16
17 <para> 17 <para>
18 The <literal>ngx_http_upstream_module</literal> module 18 The <literal>ngx_http_upstream_module</literal> module
147 147
148 <tag-name><literal>max_fails</literal>=<value>number</value></tag-name> 148 <tag-name><literal>max_fails</literal>=<value>number</value></tag-name>
149 <tag-desc> 149 <tag-desc>
150 sets the number of unsuccessful attempts to communicate with the server 150 sets the number of unsuccessful attempts to communicate with the server
151 that should happen in the duration set by the <literal>fail_timeout</literal> 151 that should happen in the duration set by the <literal>fail_timeout</literal>
152 parameter to consider the server down for a duration also set by the 152 parameter to consider the server unavailable for a duration also set by the
153 <literal>fail_timeout</literal> parameter. 153 <literal>fail_timeout</literal> parameter.
154 By default, the number of unsuccessful attempts is set to 1. 154 By default, the number of unsuccessful attempts is set to 1.
155 The zero value disables the accounting of attempts. 155 The zero value disables the accounting of attempts.
156 What is considered an unsuccessful attempt is defined by the 156 What is considered an unsuccessful attempt is defined by the
157 <link doc="ngx_http_proxy_module.xml" id="proxy_next_upstream"/>, 157 <link doc="ngx_http_proxy_module.xml" id="proxy_next_upstream"/>,
165 sets 165 sets
166 <list type="bullet"> 166 <list type="bullet">
167 167
168 <listitem> 168 <listitem>
169 the time during which the specified number of unsuccessful attempts to 169 the time during which the specified number of unsuccessful attempts to
170 communicate with the server should happen to consider the server down; 170 communicate with the server should happen to consider the server unavailable;
171 </listitem> 171 </listitem>
172 172
173 <listitem> 173 <listitem>
174 and the period of time the server will be considered down. 174 and the period of time the server will be considered unavailable.
175 </listitem> 175 </listitem>
176 176
177 </list> 177 </list>
178 By default, the parameter is set to 10 seconds. 178 By default, the parameter is set to 10 seconds.
179 </tag-desc> 179 </tag-desc>
182 <tag-desc> 182 <tag-desc>
183 sets the <value>time</value> during which the server will recover its weight 183 sets the <value>time</value> during which the server will recover its weight
184 from zero to a nominal value, when unhealthy server becomes 184 from zero to a nominal value, when unhealthy server becomes
185 <link id="health_check">healthy</link>, 185 <link id="health_check">healthy</link>,
186 or when the server becomes available after a period of time 186 or when the server becomes available after a period of time
187 it was considered down. 187 it was considered unavailable.
188 Default value is zero, i.e. slow start is disabled. 188 Default value is zero, i.e. slow start is disabled.
189 <note> 189 <note>
190 This functionality is available as part of our <commercial_version/> only. 190 This functionality is available as part of our <commercial_version/> only.
191 </note> 191 </note>
192 </tag-desc> 192 </tag-desc>
193 193
194 <tag-name><literal>backup</literal></tag-name> 194 <tag-name><literal>backup</literal></tag-name>
195 <tag-desc> 195 <tag-desc>
196 marks the server as a backup server. 196 marks the server as a backup server.
197 It will be passed requests when the primary servers are down. 197 It will be passed requests when the primary servers are unavailable.
198 </tag-desc> 198 </tag-desc>
199 199
200 <tag-name><literal>down</literal></tag-name> 200 <tag-name><literal>down</literal></tag-name>
201 <tag-desc> 201 <tag-desc>
202 marks the server as permanently down; used along with 202 marks the server as permanently unavailable; used along with
203 the <link id="ip_hash"/> directive. 203 the <link id="ip_hash"/> directive.
204 </tag-desc> 204 </tag-desc>
205 205
206 </list> 206 </list>
207 </para> 207 </para>
255 Specifies that a group should use a load balancing method where requests 255 Specifies that a group should use a load balancing method where requests
256 are distributed between servers based on client IP addresses. 256 are distributed between servers based on client IP addresses.
257 The first three octets of the client IPv4 address, or the entire IPv6 address, 257 The first three octets of the client IPv4 address, or the entire IPv6 address,
258 are used as a hashing key. 258 are used as a hashing key.
259 The method ensures that requests from the same client will always be 259 The method ensures that requests from the same client will always be
260 passed to the same server except when this server is considered down. 260 passed to the same server except when this server is unavailable.
261 In the latter case client requests will be passed to another server. 261 In the latter case client requests will be passed to another server.
262 Most probably, it will always be the same server as well. 262 Most probably, it will always be the same server as well.
263 <note> 263 <note>
264 IPv6 addresses are supported starting from versions 1.3.2 and 1.2.2. 264 IPv6 addresses are supported starting from versions 1.3.2 and 1.2.2.
265 </note> 265 </note>
934 http://127.0.0.1/upstream_conf?add=&amp;upstream=appservers&amp;backup=&amp;server=127.0.0.1:8080 934 http://127.0.0.1/upstream_conf?add=&amp;upstream=appservers&amp;backup=&amp;server=127.0.0.1:8080
935 </example> 935 </example>
936 936
937 To add a new primary server to the group, 937 To add a new primary server to the group,
938 set its parameters to non-default values 938 set its parameters to non-default values
939 and mark it as “<literal>down</literal>” by sending: 939 and mark it as “<literal>down</literal>”, send:
940 <example> 940 <example>
941 http://127.0.0.1/upstream_conf?add=&amp;upstream=appservers&amp;server=127.0.0.1:8080&amp;weight=2&amp;max_fails=3&amp;fail_timeout=3s&amp;down= 941 http://127.0.0.1/upstream_conf?add=&amp;upstream=appservers&amp;server=127.0.0.1:8080&amp;weight=2&amp;max_fails=3&amp;fail_timeout=3s&amp;down=
942 </example> 942 </example>
943 </para> 943 </para>
944 944