Getting random "http first read error: EOF" errors in varnish
<p>I'm seeing the following 503 error in varnish from time to time in the logs:</p>

<pre><code>*   &lt;&lt; BeReq    &gt;&gt; 213585014 
-   Begin          bereq 213585013 fetch
-   Timestamp      Start: 1452675822.032332 0.000000 0.000000
-   BereqMethod    GET
-   BereqURL       /client/hedge-funds-asset-managers/
-   BereqProtocol  HTTP/1.1
-   BereqHeader    X-Real-IP: 123.125.71.28
-   BereqHeader    Host: XXXXXXXXXXXXXXXXXXX
-   BereqHeader    X-Forwarded-Proto: http
-   BereqHeader    User-Agent: Mozilla/5.0 (compatible; Baiduspider/2.0; +http://www.baidu.com/search/spider.html)
-   BereqHeader    Accept-Encoding: gzip
-   BereqHeader    Accept-Language: zh-cn,zh-tw
-   BereqHeader    Accept: */*
-   BereqHeader    X-Forwarded-For: 172.18.210.22
-   BereqHeader    X-Varnish: 213585014
-   VCL_call       BACKEND_FETCH
-   VCL_return     fetch
-   BackendOpen    232 reload_2016-01-12T07:28:50.cp_12 162.251.80.23 80 172.18.210.71 40019
-   Timestamp      Bereq: 1452675822.047840 0.015508 0.015508
-   FetchError     http first read error: EOF
-   BackendClose   232 reload_2016-01-12T07:28:50.cp_12
-   Timestamp      Beresp: 1452675876.038544 54.006212 53.990704
-   Timestamp      Error: 1452675876.038555 54.006223 0.000010
-   BerespProtocol HTTP/1.1
-   BerespStatus   503
-   BerespReason   Service Unavailable
-   BerespReason   Backend fetch failed
-   BerespHeader   Date: Wed, 13 Jan 2016 09:04:36 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: Wed, 13 Jan 2016 09:04:36 GMT
-   ObjHeader      Server: Varnish
-   ObjHeader      Content-Type: text/html; charset=utf-8
-   ObjHeader      Retry-After: 5
-   Length         286
-   BereqAcct      350 0 350 0 0 0
-   End
</code></pre>

<p>The issue is not with the backend connection because a curl to the same URL from the varnish server works fine. The version of varnish is 4.1.0. I'm not sure what "http first read error: EOF" means and any light on this issue is appreciated. Due to the random nature of this issue, I do not have any way to reproduce it as well.</p>