Child process recurrently being restarted
Guillaume Quintard
guillaume at varnish-software.com
Wed Jun 28 15:43:55 CEST 2017
Yeah, I was wondering about Transient, but it seems under control.
Apart from moving away from file storage, I have nothing at the moment :-/
--
Guillaume Quintard
On Wed, Jun 28, 2017 at 3:39 PM, Stefano Baldo <stefanobaldo at gmail.com>
wrote:
> Hi.
>
> root at 2c6c325b279f:/# varnishstat -1 | grep g_bytes
> SMA.Transient.g_bytes 519022 . Bytes
> outstanding
> SMF.s0.g_bytes 23662845952 . Bytes
> outstanding
>
> You mean g_bytes from SMA.Transient? I have set no malloc storage.
>
>
> On Wed, Jun 28, 2017 at 10:26 AM, Guillaume Quintard <
> guillaume at varnish-software.com> wrote:
>
>> Hi,
>>
>> can you look that "varnishstat -1 | grep g_bytes" and see if if matches
>> the memory you are seeing?
>>
>> --
>> Guillaume Quintard
>>
>> On Wed, Jun 28, 2017 at 3:20 PM, Stefano Baldo <stefanobaldo at gmail.com>
>> wrote:
>>
>>> Hi Guillaume.
>>>
>>> I increased the cli_timeout yesterday to 900sec (15min) and it restarted
>>> anyway, which seems to indicate that the thread is really stalled.
>>>
>>> This was 1 minute after the last restart:
>>>
>>> MAIN.n_object 3908216 . object structs made
>>> SMF.s0.g_alloc 7794510 . Allocations outstanding
>>>
>>> I've just changed the I/O Scheduler to noop to see what happens.
>>>
>>> One interest thing I've found is about the memory usage.
>>>
>>> In the 1st minute of use:
>>> MemTotal: 3865572 kB
>>> MemFree: 120768 kB
>>> MemAvailable: 2300268 kB
>>>
>>> 1 minute before a restart:
>>> MemTotal: 3865572 kB
>>> MemFree: 82480 kB
>>> MemAvailable: 68316 kB
>>>
>>> It seems like the system is possibly running out of memory.
>>>
>>> When calling varnishd, I'm specifying only "-s file,..." as storage. I
>>> see in some examples that is common to use "-s file" AND "-s malloc"
>>> together. Should I be passing "-s malloc" as well to somehow try to limit
>>> the memory usage by varnishd?
>>>
>>> Best,
>>> Stefano
>>>
>>>
>>> On Wed, Jun 28, 2017 at 4:12 AM, Guillaume Quintard <
>>> guillaume at varnish-software.com> wrote:
>>>
>>>> Sadly, nothing suspicious here, you can still try:
>>>> - bumping the cli_timeout
>>>> - changing your disk scheduler
>>>> - changing the advice option of the file storage
>>>>
>>>> I'm still convinced this is due to Varnish getting stuck waiting for
>>>> the disk because of the file storage fragmentation.
>>>>
>>>> Maybe you could look at SMF.*.g_alloc and compare it to the number of
>>>> objects. Ideally, we would have a 1:1 relation between objects and
>>>> allocations. If that number drops prior to a restart, that would be a good
>>>> clue.
>>>>
>>>>
>>>> --
>>>> Guillaume Quintard
>>>>
>>>> On Tue, Jun 27, 2017 at 11:07 PM, Stefano Baldo <stefanobaldo at gmail.com
>>>> > wrote:
>>>>
>>>>> Hi Guillaume.
>>>>>
>>>>> It keeps restarting.
>>>>> Would you mind taking a quick look in the following VCL file to check
>>>>> if you find anything suspicious?
>>>>>
>>>>> Thank you very much.
>>>>>
>>>>> Best,
>>>>> Stefano
>>>>>
>>>>> vcl 4.0;
>>>>>
>>>>> import std;
>>>>>
>>>>> backend default {
>>>>> .host = "sites-web-server-lb";
>>>>> .port = "80";
>>>>> }
>>>>>
>>>>> include "/etc/varnish/bad_bot_detection.vcl";
>>>>>
>>>>> sub vcl_recv {
>>>>> call bad_bot_detection;
>>>>>
>>>>> if (req.url == "/nocache" || req.url == "/version") {
>>>>> return(pass);
>>>>> }
>>>>>
>>>>> unset req.http.Cookie;
>>>>> if (req.method == "PURGE") {
>>>>> ban("obj.http.x-host == " + req.http.host + " &&
>>>>> obj.http.x-user-agent !~ Googlebot");
>>>>> return(synth(750));
>>>>> }
>>>>>
>>>>> set req.url = regsuball(req.url, "(?<!(http:|https))\/+", "/");
>>>>> }
>>>>>
>>>>> sub vcl_synth {
>>>>> if (resp.status == 750) {
>>>>> set resp.status = 200;
>>>>> synthetic("PURGED => " + req.url);
>>>>> return(deliver);
>>>>> } elsif (resp.status == 501) {
>>>>> set resp.status = 200;
>>>>> set resp.http.Content-Type = "text/html; charset=utf-8";
>>>>> synthetic(std.fileread("/etc/varnish/pages/invalid_domain.html"));
>>>>> return(deliver);
>>>>> }
>>>>> }
>>>>>
>>>>> sub vcl_backend_response {
>>>>> unset beresp.http.Set-Cookie;
>>>>> set beresp.http.x-host = bereq.http.host;
>>>>> set beresp.http.x-user-agent = bereq.http.user-agent;
>>>>>
>>>>> if (bereq.url == "/themes/basic/assets/theme.min.css"
>>>>> || bereq.url == "/api/events/PAGEVIEW"
>>>>> || bereq.url ~ "^\/assets\/img\/") {
>>>>> set beresp.http.Cache-Control = "max-age=0";
>>>>> } else {
>>>>> unset beresp.http.Cache-Control;
>>>>> }
>>>>>
>>>>> if (beresp.status == 200 ||
>>>>> beresp.status == 301 ||
>>>>> beresp.status == 302 ||
>>>>> beresp.status == 404) {
>>>>> if (bereq.url ~ "\&ordenar=aleatorio$") {
>>>>> set beresp.http.X-TTL = "1d";
>>>>> set beresp.ttl = 1d;
>>>>> } else {
>>>>> set beresp.http.X-TTL = "1w";
>>>>> set beresp.ttl = 1w;
>>>>> }
>>>>> }
>>>>>
>>>>> if (bereq.url !~ "\.(jpeg|jpg|png|gif|gz|tgz|bz2|tbz|mp3|ogg|swf|flv)$")
>>>>> {
>>>>> set beresp.do_gzip = true;
>>>>> }
>>>>> }
>>>>>
>>>>> sub vcl_pipe {
>>>>> set bereq.http.connection = "close";
>>>>> return (pipe);
>>>>> }
>>>>>
>>>>> sub vcl_deliver {
>>>>> unset resp.http.x-host;
>>>>> unset resp.http.x-user-agent;
>>>>> }
>>>>>
>>>>> sub vcl_backend_error {
>>>>> if (beresp.status == 502 || beresp.status == 503 || beresp.status ==
>>>>> 504) {
>>>>> set beresp.status = 200;
>>>>> set beresp.http.Content-Type = "text/html; charset=utf-8";
>>>>> synthetic(std.fileread("/etc/varnish/pages/maintenance.html"));
>>>>> return (deliver);
>>>>> }
>>>>> }
>>>>>
>>>>> sub vcl_hash {
>>>>> if (req.http.User-Agent ~ "Google Page Speed") {
>>>>> hash_data("Google Page Speed");
>>>>> } elsif (req.http.User-Agent ~ "Googlebot") {
>>>>> hash_data("Googlebot");
>>>>> }
>>>>> }
>>>>>
>>>>> sub vcl_deliver {
>>>>> if (resp.status == 501) {
>>>>> return (synth(resp.status));
>>>>> }
>>>>> if (obj.hits > 0) {
>>>>> set resp.http.X-Cache = "hit";
>>>>> } else {
>>>>> set resp.http.X-Cache = "miss";
>>>>> }
>>>>> }
>>>>>
>>>>>
>>>>> On Mon, Jun 26, 2017 at 3:47 PM, Guillaume Quintard <
>>>>> guillaume at varnish-software.com> wrote:
>>>>>
>>>>>> Nice! It may have been the cause, time will tell.can you report back
>>>>>> in a few days to let us know?
>>>>>> --
>>>>>> Guillaume Quintard
>>>>>>
>>>>>> On Jun 26, 2017 20:21, "Stefano Baldo" <stefanobaldo at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> Hi Guillaume.
>>>>>>>
>>>>>>> I think things will start to going better now after changing the
>>>>>>> bans.
>>>>>>> This is how my last varnishstat looked like moments before a crash
>>>>>>> regarding the bans:
>>>>>>>
>>>>>>> MAIN.bans 41336 . Count of bans
>>>>>>> MAIN.bans_completed 37967 . Number of bans
>>>>>>> marked 'completed'
>>>>>>> MAIN.bans_obj 0 . Number of bans
>>>>>>> using obj.*
>>>>>>> MAIN.bans_req 41335 . Number of bans
>>>>>>> using req.*
>>>>>>> MAIN.bans_added 41336 0.68 Bans added
>>>>>>> MAIN.bans_deleted 0 0.00 Bans deleted
>>>>>>>
>>>>>>> And this is how it looks like now:
>>>>>>>
>>>>>>> MAIN.bans 2 . Count of bans
>>>>>>> MAIN.bans_completed 1 . Number of bans
>>>>>>> marked 'completed'
>>>>>>> MAIN.bans_obj 2 . Number of bans
>>>>>>> using obj.*
>>>>>>> MAIN.bans_req 0 . Number of bans
>>>>>>> using req.*
>>>>>>> MAIN.bans_added 2016 0.69 Bans added
>>>>>>> MAIN.bans_deleted 2014 0.69 Bans deleted
>>>>>>>
>>>>>>> Before the changes, bans were never deleted!
>>>>>>> Now the bans are added and quickly deleted after a minute or even a
>>>>>>> couple of seconds.
>>>>>>>
>>>>>>> May this was the cause of the problem? It seems like varnish was
>>>>>>> having a large number of bans to manage and test against.
>>>>>>> I will let it ride now. Let's see if the problem persists or it's
>>>>>>> gone! :-)
>>>>>>>
>>>>>>> Best,
>>>>>>> Stefano
>>>>>>>
>>>>>>>
>>>>>>> On Mon, Jun 26, 2017 at 3:10 PM, Guillaume Quintard <
>>>>>>> guillaume at varnish-software.com> wrote:
>>>>>>>
>>>>>>>> Looking good!
>>>>>>>>
>>>>>>>> --
>>>>>>>> Guillaume Quintard
>>>>>>>>
>>>>>>>> On Mon, Jun 26, 2017 at 7:06 PM, Stefano Baldo <
>>>>>>>> stefanobaldo at gmail.com> wrote:
>>>>>>>>
>>>>>>>>> Hi Guillaume,
>>>>>>>>>
>>>>>>>>> Can the following be considered "ban lurker friendly"?
>>>>>>>>>
>>>>>>>>> sub vcl_backend_response {
>>>>>>>>> set beresp.http.x-url = bereq.http.host + bereq.url;
>>>>>>>>> set beresp.http.x-user-agent = bereq.http.user-agent;
>>>>>>>>> }
>>>>>>>>>
>>>>>>>>> sub vcl_recv {
>>>>>>>>> if (req.method == "PURGE") {
>>>>>>>>> ban("obj.http.x-url == " + req.http.host + req.url + " &&
>>>>>>>>> obj.http.x-user-agent !~ Googlebot");
>>>>>>>>> return(synth(750));
>>>>>>>>> }
>>>>>>>>> }
>>>>>>>>>
>>>>>>>>> sub vcl_deliver {
>>>>>>>>> unset resp.http.x-url;
>>>>>>>>> unset resp.http.x-user-agent;
>>>>>>>>> }
>>>>>>>>>
>>>>>>>>> Best,
>>>>>>>>> Stefano
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Mon, Jun 26, 2017 at 12:43 PM, Guillaume Quintard <
>>>>>>>>> guillaume at varnish-software.com> wrote:
>>>>>>>>>
>>>>>>>>>> Not lurker friendly at all indeed. You'll need to avoid req.*
>>>>>>>>>> expression. Easiest way is to stash the host, user-agent and url in
>>>>>>>>>> beresp.http.* and ban against those (unset them in vcl_deliver).
>>>>>>>>>>
>>>>>>>>>> I don't think you need to expand the VSL at all.
>>>>>>>>>>
>>>>>>>>>> --
>>>>>>>>>> Guillaume Quintard
>>>>>>>>>>
>>>>>>>>>> On Jun 26, 2017 16:51, "Stefano Baldo" <stefanobaldo at gmail.com>
>>>>>>>>>> wrote:
>>>>>>>>>>
>>>>>>>>>> Hi Guillaume.
>>>>>>>>>>
>>>>>>>>>> Thanks for answering.
>>>>>>>>>>
>>>>>>>>>> I'm using a SSD disk. I've changed from ext4 to ext2 to increase
>>>>>>>>>> performance but it stills restarting.
>>>>>>>>>> Also, I checked the I/O performance for the disk and there is no
>>>>>>>>>> signal of overhead.
>>>>>>>>>>
>>>>>>>>>> I've changed the /var/lib/varnish to a tmpfs and increased its
>>>>>>>>>> 80m default size passing "-l 200m,20m" to varnishd and using
>>>>>>>>>> "nodev,nosuid,noatime,size=256M 0 0" for the tmpfs mount. There
>>>>>>>>>> was a problem here. After a couple of hours varnish died and I received a
>>>>>>>>>> "no space left on device" message - deleting the /var/lib/varnish solved
>>>>>>>>>> the problem and varnish was up again, but it's weird because there was free
>>>>>>>>>> memory on the host to be used with the tmpfs directory, so I don't know
>>>>>>>>>> what could have happened. I will try to stop increasing the
>>>>>>>>>> /var/lib/varnish size.
>>>>>>>>>>
>>>>>>>>>> Anyway, I am worried about the bans. You asked me if the bans are
>>>>>>>>>> lurker friedly. Well, I don't think so. My bans are created this way:
>>>>>>>>>>
>>>>>>>>>> ban("req.http.host == " + req.http.host + " && req.url ~ " +
>>>>>>>>>> req.url + " && req.http.User-Agent !~ Googlebot");
>>>>>>>>>>
>>>>>>>>>> Are they lurker friendly? I was taking a quick look and the
>>>>>>>>>> documentation and it looks like they're not.
>>>>>>>>>>
>>>>>>>>>> Best,
>>>>>>>>>> Stefano
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On Fri, Jun 23, 2017 at 11:30 AM, Guillaume Quintard <
>>>>>>>>>> guillaume at varnish-software.com> wrote:
>>>>>>>>>>
>>>>>>>>>>> Hi Stefano,
>>>>>>>>>>>
>>>>>>>>>>> Let's cover the usual suspects: I/Os. I think here Varnish gets
>>>>>>>>>>> stuck trying to push/pull data and can't make time to reply to the CLI. I'd
>>>>>>>>>>> recommend monitoring the disk activity (bandwidth and iops) to confirm.
>>>>>>>>>>>
>>>>>>>>>>> After some time, the file storage is terrible on a hard drive
>>>>>>>>>>> (SSDs take a bit more time to degrade) because of fragmentation. One
>>>>>>>>>>> solution to help the disks cope is to overprovision themif they're SSDs,
>>>>>>>>>>> and you can try different advices in the file storage definition in the
>>>>>>>>>>> command line (last parameter, after granularity).
>>>>>>>>>>>
>>>>>>>>>>> Is your /var/lib/varnish mount on tmpfs? That could help too.
>>>>>>>>>>>
>>>>>>>>>>> 40K bans is a lot, are they ban-lurker friendly?
>>>>>>>>>>>
>>>>>>>>>>> --
>>>>>>>>>>> Guillaume Quintard
>>>>>>>>>>>
>>>>>>>>>>> On Fri, Jun 23, 2017 at 4:01 PM, Stefano Baldo <
>>>>>>>>>>> stefanobaldo at gmail.com> wrote:
>>>>>>>>>>>
>>>>>>>>>>>> Hello.
>>>>>>>>>>>>
>>>>>>>>>>>> I am having a critical problem with Varnish Cache in production
>>>>>>>>>>>> for over a month and any help will be appreciated.
>>>>>>>>>>>> The problem is that Varnish child process is recurrently being
>>>>>>>>>>>> restarted after 10~20h of use, with the following message:
>>>>>>>>>>>>
>>>>>>>>>>>> Jun 23 09:15:13 b858e4a8bd72 varnishd[11816]: Child (11824) not
>>>>>>>>>>>> responding to CLI, killed it.
>>>>>>>>>>>> Jun 23 09:15:13 b858e4a8bd72 varnishd[11816]: Unexpected reply
>>>>>>>>>>>> from ping: 400 CLI communication error
>>>>>>>>>>>> Jun 23 09:15:13 b858e4a8bd72 varnishd[11816]: Child (11824)
>>>>>>>>>>>> died signal=9
>>>>>>>>>>>> Jun 23 09:15:14 b858e4a8bd72 varnishd[11816]: Child cleanup
>>>>>>>>>>>> complete
>>>>>>>>>>>> Jun 23 09:15:14 b858e4a8bd72 varnishd[11816]: Child (24038)
>>>>>>>>>>>> Started
>>>>>>>>>>>> Jun 23 09:15:14 b858e4a8bd72 varnishd[11816]: Child (24038)
>>>>>>>>>>>> said Child starts
>>>>>>>>>>>> Jun 23 09:15:14 b858e4a8bd72 varnishd[11816]: Child (24038)
>>>>>>>>>>>> said SMF.s0 mmap'ed 483183820800 bytes of 483183820800
>>>>>>>>>>>>
>>>>>>>>>>>> The following link is the varnishstat output just 1 minute
>>>>>>>>>>>> before a restart:
>>>>>>>>>>>>
>>>>>>>>>>>> https://pastebin.com/g0g5RVTs
>>>>>>>>>>>>
>>>>>>>>>>>> Environment:
>>>>>>>>>>>>
>>>>>>>>>>>> varnish-5.1.2 revision 6ece695
>>>>>>>>>>>> Debian 8.7 - Debian GNU/Linux 8 (3.16.0)
>>>>>>>>>>>> Installed using pre-built package from official repo at
>>>>>>>>>>>> packagecloud.io
>>>>>>>>>>>> CPU 2x2.9 GHz
>>>>>>>>>>>> Mem 3.69 GiB
>>>>>>>>>>>> Running inside a Docker container
>>>>>>>>>>>> NFILES=131072
>>>>>>>>>>>> MEMLOCK=82000
>>>>>>>>>>>>
>>>>>>>>>>>> Additional info:
>>>>>>>>>>>>
>>>>>>>>>>>> - I need to cache a large number of objets and the cache should
>>>>>>>>>>>> last for almost a week, so I have set up a 450G storage space, I don't know
>>>>>>>>>>>> if this is a problem;
>>>>>>>>>>>> - I use ban a lot. There was about 40k bans in the system just
>>>>>>>>>>>> before the last crash. I really don't know if this is too much or may have
>>>>>>>>>>>> anything to do with it;
>>>>>>>>>>>> - No registered CPU spikes (almost always by 30%);
>>>>>>>>>>>> - No panic is reported, the only info I can retrieve is from
>>>>>>>>>>>> syslog;
>>>>>>>>>>>> - During all the time, event moments before the crashes,
>>>>>>>>>>>> everything is okay and requests are being responded very fast.
>>>>>>>>>>>>
>>>>>>>>>>>> Best,
>>>>>>>>>>>> Stefano Baldo
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> _______________________________________________
>>>>>>>>>>>> varnish-misc mailing list
>>>>>>>>>>>> varnish-misc at varnish-cache.org
>>>>>>>>>>>> https://www.varnish-cache.org/lists/mailman/listinfo/varnish
>>>>>>>>>>>> -misc
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>
>>>>
>>>
>>
>
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