Varnish

Varnish 4.1 - 如何在後端獲取時提供記憶體副本失敗而不是 503

  • March 28, 2022

我有一個由 apache+tomcat 提供的站點和一個由 Varnish 4.1 提供的記憶體

當 apache 關閉時，varnish 總是返回 503 錯誤。

我希望清漆返回它在記憶體中的頁面副本，但我對 ttl 和 Grace 的嘗試沒有成功。

我想我已經閱讀了我能找到的所有關於 varnish 4.1 的文件，非常感謝任何幫助。

提前致謝

編輯： varnishlog -g request -q “ReqUrl eq ‘/’”

捲曲

*   << Request  >> 1410492
-   Begin          req 1410491 rxreq
-   Timestamp      Start: 1646995409.603391 0.000000 0.000000
-   Timestamp      Req: 1646995409.603391 0.000000 0.000000
-   ReqStart       10.xxx.xxx.xxx 57472
-   ReqMethod      GET
-   ReqURL         /
-   ReqProtocol    HTTP/1.1
-   ReqHeader      host: akamai5.rsi.ch
-   ReqHeader      user-agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:98.0) Gecko/20100101 Firefox/98.0
-   ReqHeader      accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8
-   ReqHeader      accept-language: it,en-US;q=0.7,en;q=0.3
-   ReqHeader      accept-encoding: gzip, deflate, br
-   ReqHeader      cookie: wt_rla=292330999892453%2C2%2C1646731482026; _pipe_c=do_not_track; _ga=GA1.2.836346559.1644414441; __gads=ID=453223b8518b57e5-22f191e137cd00c3:T=1644414444:RT=1644414444:S=ALNI_MbCUi8liJ5sbhjlTe68z1BhLhZJCQ; __utma=46365988.836346559.1644414441.16
-   ReqHeader      upgrade-insecure-requests: 1
-   ReqHeader      sec-fetch-dest: document
-   ReqHeader      sec-fetch-mode: navigate
-   ReqHeader      sec-fetch-site: none
-   ReqHeader      sec-fetch-user: ?1
-   ReqHeader      cache-control: max-age=0
-   ReqHeader      x-forwarded-proto: https
-   ReqHeader      x-forwarded-ssl: on
-   ReqHeader      x-forwarded-port: 443
-   ReqHeader      x-forwarded-for: 1178.xxx.xxx.xxx
-   ReqHeader      connection: close
-   ReqUnset       x-forwarded-for: 1178.xxx.xxx.xxx
-   ReqHeader      X-Forwarded-For: 1178.xxx.xxx.xxx, 10.xxx.xxx.xxx
-   VCL_call       RECV
-   ReqUnset       cookie: wt_rla=292330999892453%2C2%2C1646731482026; _pipe_c=do_not_track; _ga=GA1.2.836346559.1644414441; __gads=ID=453223b8518b57e5-22f191e137cd00c3:T=1644414444:RT=1644414444:S=ALNI_MbCUi8liJ5sbhjlTe68z1BhLhZJCQ; __utma=46365988.836346559.1644414441.16
-   ReqHeader      Cookie: wt_rla=292330999892453%2C2%2C1646731482026; _pipe_c=do_not_track; _ga=GA1.2.836346559.1644414441; __gads=ID=453223b8518b57e5-22f191e137cd00c3:T=1644414444:RT=1644414444:S=ALNI_MbCUi8liJ5sbhjlTe68z1BhLhZJCQ; cs_fpid=1645804349272_22538249; wt_geid
-   ReqUnset       Cookie: wt_rla=292330999892453%2C2%2C1646731482026; _pipe_c=do_not_track; _ga=GA1.2.836346559.1644414441; __gads=ID=453223b8518b57e5-22f191e137cd00c3:T=1644414444:RT=1644414444:S=ALNI_MbCUi8liJ5sbhjlTe68z1BhLhZJCQ; cs_fpid=1645804349272_22538249; wt_geid
-   ReqHeader      Cookie: wt_rla=292330999892453%2C2%2C1646731482026; _pipe_c=do_not_track; _ga=GA1.2.836346559.1644414441; __gads=ID=453223b8518b57e5-22f191e137cd00c3:T=1644414444:RT=1644414444:S=ALNI_MbCUi8liJ5sbhjlTe68z1BhLhZJCQ; cs_fpid=1645804349272_22538249; wt_geid
-   ReqUnset       Cookie: wt_rla=292330999892453%2C2%2C1646731482026; _pipe_c=do_not_track; _ga=GA1.2.836346559.1644414441; __gads=ID=453223b8518b57e5-22f191e137cd00c3:T=1644414444:RT=1644414444:S=ALNI_MbCUi8liJ5sbhjlTe68z1BhLhZJCQ; cs_fpid=1645804349272_22538249; wt_geid
-   ReqHeader      Cookie: wt_rla=292330999892453%2C2%2C1646731482026; _pipe_c=do_not_track; _ga=GA1.2.836346559.1644414441; __gads=ID=453223b8518b57e5-22f191e137cd00c3:T=1644414444:RT=1644414444:S=ALNI_MbCUi8liJ5sbhjlTe68z1BhLhZJCQ; cs_fpid=1645804349272_22538249; wt_geid
-   VCL_return     hash
-   ReqUnset       accept-encoding: gzip, deflate, br
-   ReqHeader      Accept-Encoding: gzip
-   VCL_call       HASH
-   VCL_return     lookup
-   Hit            1410469
-   VCL_call       HIT
-   VCL_return     deliver
-   RespProtocol   HTTP/1.1
-   RespStatus     200
-   RespReason     OK
-   RespHeader     Date: Fri, 11 Mar 2022 10:42:05 GMT
-   RespHeader     Server: Apache-Coyote/1.1
-   RespHeader     Content-Type: text/html;charset=UTF-8
-   RespHeader     Set-Cookie: JSESSIONID=F8D07853DF7D90A3F381B316F64FA285; Path=/; HttpOnly
-   RespHeader     X-Varnish: 1410492 1410469
-   RespHeader     Age: 84
-   RespHeader     Via: 1.1 varnish-v4
-   VCL_call       DELIVER
-   RespHeader     X-Cache-Host: rsi-prod-varnish45
-   RespHeader     X-Frame-Options: SAMEORIGIN
-   RespHeader     X-XSS-Protection: 1; mode=block
-   RespHeader     X-Content-Type-Options: nosniff
-   RespHeader     Content-Security-Policy: script-src 'self' 'unsafe-inline' 'unsafe-eval' *
-   RespHeader     X-Cache: HIT
-   RespHeader     X-Cache-Hits: 3
-   RespHeader     X-Grace-Hit: yes
-   VCL_return     deliver
-   Timestamp      Process: 1646995409.603614 0.000222 0.000222
-   RespHeader     Accept-Ranges: bytes
-   RespHeader     Content-Length: 191244
-   Debug          "RES_MODE 2"
-   RespHeader     Connection: close
-   Timestamp      Resp: 1646995409.608024 0.004632 0.004410
-   ReqAcct        1130 0 1130 574 191244 191818
-   End

瀏覽器

*   << Request  >> 1410496
-   Begin          req 1410495 rxreq
-   Timestamp      Start: 1646995426.730217 0.000000 0.000000
-   Timestamp      Req: 1646995426.730217 0.000000 0.000000
-   ReqStart       10.xxx.xxx.xxx 60908
-   ReqMethod      GET
-   ReqURL         /
-   ReqProtocol    HTTP/1.1
-   ReqHeader      host: www.example.com
-   ReqHeader      user-agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:88.0) Gecko/20100101 Firefox/88.0
-   ReqHeader      accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
-   ReqHeader      accept-language: it,it-IT;q=0.8,en-US;q=0.5,en;q=0.3
-   ReqHeader      accept-encoding: gzip, deflate, br
-   ReqHeader      cookie: _pipe_c=do_not_track; _ga=GA1.2.1217589648.1620392041; __gads=ID=1a22b33c44d55e6f-1a22b33c44d55e6f:T=1620392042:RT=1620392042:S=ALNI_MYR9nyXrxcQ8QV1Y2pNVDp67Gn9-w; __utma=46365988.1217589648.1620392041.1638545296.1642173864.10; __utmz=46365988.16
-   ReqHeader      upgrade-insecure-requests: 1
-   ReqHeader      cache-control: max-age=0
-   ReqHeader      x-forwarded-proto: https
-   ReqHeader      x-forwarded-ssl: on
-   ReqHeader      x-forwarded-port: 443
-   ReqHeader      x-forwarded-for: 178.xxx.xxx.xxx
-   ReqHeader      connection: close
-   ReqUnset       x-forwarded-for: 178.xxx.xxx.xxx
-   ReqHeader      X-Forwarded-For: 178.xxx.xxx.xxx, 10.xxx.xxx.xxx
-   VCL_call       RECV
-   ReqUnset       cookie: _pipe_c=do_not_track; _ga=GA1.2.1217589648.1620392041; __gads=ID=1a22b33c44d55e6f-1a22b33c44d55e6f:T=1620392042:RT=1620392042:S=ALNI_MYR9nyXrxcQ8QV1Y2pNVDp67Gn9-w; __utma=46365988.1217589648.1620392041.1638545296.1642173864.10; __utmz=46365988.16
-   ReqHeader      Cookie: _pipe_c=do_not_track; _ga=GA1.2.1217589648.1620392041; __gads=ID=1a22b33c44d55e6f-1a22b33c44d55e6f:T=1620392042:RT=1620392042:S=ALNI_MYR9nyXrxcQ8QV1Y2pNVDp67Gn9-w; wt_rla=292330999892453%2C2%2C1646995242972; cs_fpid=1645855325408_55998969; JSESSI
-   ReqUnset       Cookie: _pipe_c=do_not_track; _ga=GA1.2.1217589648.1620392041; __gads=ID=1a22b33c44d55e6f-1a22b33c44d55e6f:T=1620392042:RT=1620392042:S=ALNI_MYR9nyXrxcQ8QV1Y2pNVDp67Gn9-w; wt_rla=292330999892453%2C2%2C1646995242972; cs_fpid=1645855325408_55998969; JSESSI
-   ReqHeader      Cookie: _pipe_c=do_not_track; _ga=GA1.2.1217589648.1620392041; __gads=ID=1a22b33c44d55e6f-1a22b33c44d55e6f:T=1620392042:RT=1620392042:S=ALNI_MYR9nyXrxcQ8QV1Y2pNVDp67Gn9-w; wt_rla=292330999892453%2C2%2C1646995242972; cs_fpid=1645855325408_55998969; JSESSI
-   ReqUnset       Cookie: _pipe_c=do_not_track; _ga=GA1.2.1217589648.1620392041; __gads=ID=1a22b33c44d55e6f-1a22b33c44d55e6f:T=1620392042:RT=1620392042:S=ALNI_MYR9nyXrxcQ8QV1Y2pNVDp67Gn9-w; wt_rla=292330999892453%2C2%2C1646995242972; cs_fpid=1645855325408_55998969; JSESSI
-   ReqHeader      Cookie: _pipe_c=do_not_track; _ga=GA1.2.1217589648.1620392041; __gads=ID=1a22b33c44d55e6f-1a22b33c44d55e6f:T=1620392042:RT=1620392042:S=ALNI_MYR9nyXrxcQ8QV1Y2pNVDp67Gn9-w; wt_rla=292330999892453%2C2%2C1646995242972; cs_fpid=1645855325408_55998969; JSESSI
-   VCL_return     hash
-   ReqUnset       accept-encoding: gzip, deflate, br
-   ReqHeader      Accept-Encoding: gzip
-   VCL_call       HASH
-   VCL_return     lookup
-   VCL_call       MISS
-   VCL_return     fetch
-   Link           bereq 1410497 fetch
-   Timestamp      Fetch: 1646995426.730455 0.000238 0.000238
-   RespProtocol   HTTP/1.1
-   RespStatus     503
-   RespReason     Backend fetch failed
-   RespHeader     Date: Fri, 11 Mar 2022 10:43:46 GMT
-   RespHeader     Server: Varnish
-   RespHeader     Content-Type: text/html; charset=utf-8
-   RespHeader     Retry-After: 5
-   RespHeader     X-Varnish: 1410496
-   RespHeader     Age: 0
-   RespHeader     Via: 1.1 varnish-v4
-   VCL_call       DELIVER
-   RespHeader     X-Cache-Host: rsi-prod-varnish45
-   RespHeader     X-Frame-Options: SAMEORIGIN
-   RespHeader     X-XSS-Protection: 1; mode=block
-   RespHeader     X-Content-Type-Options: nosniff
-   RespHeader     Content-Security-Policy: script-src 'self' 'unsafe-inline' 'unsafe-eval' *
-   RespHeader     X-Cache: HIT
-   RespHeader     X-Cache-Hits: 0
-   RespHeader     X-Grace-Hit: yes
-   VCL_return     deliver
-   Timestamp      Process: 1646995426.730495 0.000278 0.000040
-   RespHeader     Content-Length: 284
-   Debug          "RES_MODE 2"
-   RespHeader     Connection: close
-   Timestamp      Resp: 1646995426.730527 0.000310 0.000032
-   ReqAcct        929 0 929 490 284 774
-   End
**  << BeReq    >> 1410497
--  Begin          bereq 1410496 fetch
--  Timestamp      Start: 1646995426.730367 0.000000 0.000000
--  BereqMethod    GET
--  BereqURL       /
--  BereqProtocol  HTTP/1.1
--  BereqHeader    host: www.example.com
--  BereqHeader    user-agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:88.0) Gecko/20100101 Firefox/88.0
--  BereqHeader    accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
--  BereqHeader    accept-language: it,it-IT;q=0.8,en-US;q=0.5,en;q=0.3
--  BereqHeader    upgrade-insecure-requests: 1
--  BereqHeader    x-forwarded-proto: https
--  BereqHeader    x-forwarded-ssl: on
--  BereqHeader    x-forwarded-port: 443
--  BereqHeader    X-Forwarded-For: 178.xxx.xxx.xxx, 10.xxx.xxx.xxx
--  BereqHeader    Cookie: _pipe_c=do_not_track; _ga=GA1.2.1217589648.1620392041; __gads=ID=1a22b33c44d55e6f-1a22b33c44d55e6f:T=1620392042:RT=1620392042:S=ALNI_MYR9nyXrxcQ8QV1Y2pNVDp67Gn9-w; wt_rla=292330999892453%2C2%2C1646995242972; cs_fpid=1645855325408_55998969; JSESSI
--  BereqHeader    Accept-Encoding: gzip
--  BereqHeader    X-Varnish: 1410497
--  VCL_call       BACKEND_FETCH
--  VCL_Log        Backend fetch: v_ssl_ece
--  VCL_return     fetch
--  FetchError     Director v_ssl_ece returned no backend
--  FetchError     No backend
--  Timestamp      Beresp: 1646995426.730387 0.000020 0.000020
--  Timestamp      Error: 1646995426.730390 0.000023 0.000003
--  BerespProtocol HTTP/1.1
--  BerespStatus   503
--  BerespReason   Service Unavailable
--  BerespReason   Backend fetch failed
--  BerespHeader   Date: Fri, 11 Mar 2022 10:43:46 GMT
--  BerespHeader   Server: Varnish
--  VCL_call       BACKEND_ERROR
--  BerespHeader   Content-Type: text/html; charset=utf-8
--  BerespHeader   Retry-After: 5
--  VCL_return     deliver
--  Storage        malloc Transient
--  ObjProtocol    HTTP/1.1
--  ObjStatus      503
--  ObjReason      Backend fetch failed
--  ObjHeader      Date: Fri, 11 Mar 2022 10:43:46 GMT
--  ObjHeader      Server: Varnish
--  ObjHeader      Content-Type: text/html; charset=utf-8
--  ObjHeader      Retry-After: 5
--  Length         284
--  BereqAcct      0 0 0 0 0 0
--  End

編輯 2：雜湊和 cookie

經過大量調查，我們發現問題出在此配置上：

sub vcl_hash {
 hash_data( req.url );
 if( req.http.host ) {
   hash_data( req.http.host );
 } else {
   hash_data( server.ip );
 }
 # hash cookies for object with auth
 if( req.http.Cookie ) {
   hash_data( req.http.Cookie );
 }
 return( lookup );
}

如果 cookie 從清漆散列中刪除，它會正確返回記憶體。將 cookie 包含在雜湊中是否有用？乍一看，我認為是這樣，如果使用 cookie 來跟踪使用者身份驗證。我們如何才能在散列中只包含某些 cookie（例如來自經過身份驗證的會話的那些），而不包含那些對記憶體無用的 cookie（例如與分析相關的那些）？

只要 TTL 和寬限值之和大於零，就不會進行後端提取。

如果您的 TTL 過期，寬限模式將確保在嘗試獲取時提供過時的內容。

Grace 是一種stale-while-revalidate機制，實際上可以被濫用並變成stale-if-error機制。通過將寬限設置得足夠高，使用者將永遠不會遇到後端的停機時間。

這是一些VCL：

vcl 4.1;

import std;

sub vcl_recv {
   if (std.healthy(req.backend_hint)) {
       set req.grace = 10s;
   }
}

sub vcl_backend_response {
   set beresp.grace = 24h;
}

此 VCL 程式碼將強制執行 24 小時寬限期。這意味著您的後端可能會在沒有人注意到的情況下關閉一天。但是，只要後端是健康的，Varnish 只會使用 10 秒的寬限期。

重要的是您的後端定義具有.probe引用健康檢查探針的屬性，否則std.healthy(req.backend_hint)將永遠無法產生正確的結果。

我用過set beresp.grace = 24h可能過分的。通過將寬限設置為如此長的持續時間，這些對像在過期時仍保留在記憶體中。如果您有大量需要記憶體的內容目錄，這可能會影響您的命中率，並且可能會在記憶體已滿時導致強制記憶體逐出。

重要提示： Varnish Cache 4.1 已報廢，不應使用。請改為安裝 Varnish 6.0 LTS 或 Varnish 7。

我的 VCL 範例包含一個vcl 4.1;僅適用於 Varnish 6 或 Varnish 7 的版本標記。我這樣做是為了鼓勵使用者使用最新版本的 Varnish。通過將其切換到vcl 4.0;程式碼可能會在舊版本的 Varnish 上工作。請考慮升級。

503 錯誤

根據您添加到問題中的 VSL 輸出，我可以得出結論，您已經在 VCL 中定義並使用了一個沒有任何後端的導向器對象。

這是我在您的 VSL 輸出中發現的錯誤：

Director v_ssl_ece returned no backend

請看一下名為的導演v_ssl_ece。

  • 檢查你是否需要這個導演
  • 檢查是否通過req.backend_hintinvcl_recv或 through bereq.backendin正確分配vcl_backend_fetch
  • 檢查為什麼v_ssl_ece沒有任何後端

如果您找不到解決方案，請分享您的完整 VCL 文件，以便我提供幫助。

引用自：https://serverfault.com/questions/1095343

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