Search for:
Magento 2 tutorial
Fixing magento issues

[SOLVED] Magento 2 Error 503 Backend fetch failed with varnish cache

3 Mins Read
Pinterest LinkedIn Tumblr

Magento 2 comes with many complicated features which makes it one of the most powerful open source Ecommerce platform at the moment. However, due to its complexity, there are many type of error may occur when working with Magento.

One of the most common error that Magento 2 user encounter is 503 Backend fetch failed with varnish cache

magento 2 503 error

In this series of tutorials on fixing Magento 2 issues, I will guide you all the possible causes of the error and of course, the solution to resolve the error.

Note: In case you see the error message: Error 503 service temporarily unavailable, read this tutorial to learn how to fix it => How to fix Magento 2 Error 503 service temporarily unavailable

Possible causes of the error and solution

1. Length of cache tags used by Magento exceed Varnish’s default value

If your store has a large number of products (more than 400), the error may happen because the length of cache tags used by Magento 2 exceed the default value of Varnish. The default value of Varnish is 8192 bytes, which mean it is only stable for a store with less than 400 products. (safe http_resp_hdr_len value = product number multiplied by 21)

Solution

We will change http_resp_hdr_len value in Varnish configuration file. (Maximum length of any HTTP backend response header – read here for more detail)

The path to varnish configuration file is

  • Ubuntu: /etc/default/varnish
  • Centos 6 : /etc/sysconfig/varnish
  • Centos 7: /etc/varnish/varnish.params

Edit the file with a text editor and change the http_resp_hdr_len value (located in line 101 after thread_pool_max )

-p http_resp_hdr_len=8192 \

to larger value (for example, 70000 bytes should work well for 3000+ products)

-p http_resp_hdr_len=70000 \

Also, change http_resp_size (Maximum number of bytes of HTTP backend response) to the value that fit the increased value of http_resp_hdr_len , for example 10000 http_resp_size should be good with 70000 http_resp_hdr_len

-p http_resp_size=100000 \

It should be like this after you make change

http_resp_hdr_len

Finally, save file and restart Magento 2 server to apply changes.

2. Wrong health_check.php location in Varnish config file

The other possibility that caused 503 error is wrong health_check.php file location in varnish configuration file. This usually happens even with a fresh installation of Magento 2 (frequently reported in Magento 2.3)

By default, the path to health_check.php file in varnish is /pub/health_check.php.

In Magento 2, nginx.conf.sample already set root path to /pub => wrong path in varnish configuration file. We will change this to the correct path.

Solution

Go to Varnish configuration file (/etc/varnish/default.vcl) and find these lines

    .probe = {
        .url = "/pub/health_check.php";

Change it to

    .probe = {
        .url = "/health_check.php";

Also, go to nginx.conf.sample file in Magento 2 root folder, find the following lines:

location ~ (index|get|static|report|404|503)\.php$ {

Add health_check to this line to allow health_check.php file as below

location ~ (index|get|static|report|404|503|health_check)\.php$ {

Save changes and restart varnish and nginx to apply change. Now your site should be working properly

3. Maintenance.flag file generated by Magento 2

Another cause of the 503 error may be the var/.maintenance.flag file, which is generated by Magento 2 when you install new extensions/theme or maintaining, upgrading, or reconfiguring your site.

maintenance.flag

Solution

Open file manager and rename/remove maintenance.flag file and refresh your website to see if the error is solved.

Conclusion

I hope this tutorial helps you resolve Magento 2 Error 503 Backend fetch failed with varnish cache. If your site still does not work after trying the solution in this tutorial, please drop a line in the comment section with link to your site. I will examine and help you fix if possible.

Hung Tran is the main editor of magentip.com, he loves to write about everything related to Magento 2

Related Posts

205 Comments

  1. McDoogle

    Why does health check mail varnish fail? I have the same issue over the last few magentos since 2.1

  2. Hung Tran Post Author

    What was the full error message?
    You should check if health_check.php location was wrong in Varnish config file

  3. Rahul Kesharwani

    Hi Hung,

    I have tried all the mentioned steps and also many workarounds but still the frontend and backend is not loading without https. The URL is not automatically redirecting to https when varnish is configured.

  5. deutsch

    Uotdoor striop partyVirgin boys videoBig black ddicks suckedAsiqn ssweat annd sour
    sauceNauggty mpmmy seex storiesExtrdme sklull fuk pukeBaenyard ssex fuckCloe upp puszy
    spreadingTraci lords lewsbian sceneRealigy kings vidro clips sexBouncing boobs onn
    yahoo videoUncle henry’s cockMisss ssuzi transgenderedSicck sknny
    irls fuckedStrip ckubs in bwttle creekDrew royy nakedAdult teern search enginesAssian skin lightenersLingerie gallery free picWantt give maan grreat boow jobGirl iin lleggings fetishAsian dting
    gorl singleFetiksh breastmilkBack girll vintageSacramento
    kints dancde tem nudee photosErotic neew year’s eve
    partiesMature srocking clipsModels pphoto shoting sluut loadNauthy amateurFreee xxxx
    cliphunterFinancing a teens new carCllip coock hugeHentai disfipline academy series streamzCyber bullyiing andd ten suicideCarttoon moiving sexx picsDildo masterbatingGlass inn pantyhoseDick fucck a ute asuan girlMiilf nicoleNarciasistic paranoid
    deeption lies sexualFree poirn movvies crystal clearSanta claus having ssex
    with manWholesale adjlt dvd’sAmerican piee bajd cam stripGay maloe seex toyiesOf human bondsage discussioon questionsFreee nude simpson picturesCool luch oxes ffor aduylts bentoMy anus iss bleeding clipFreak ebonyys pound assTrade brrast forms3d xxx sex worldVntage chessi mooreBarbb petrfo sexDifferrent breast sizaes
    chartXxxx cofk cumUn shawved vaginaTeedns hoot
    orn videosGirll hhairy latinoaaron pornstarLesbiann dating neww jerseyExpllited bblack tedens angioe litaTeeen amaeur
    hennessie spreads herr legsInnocent skinny blonde tewen fuckedEroyic flighht attendentsXxxx fat pornJennufer love hewitt
    bouncy boobsAdullt educatioon maDoouble vaginal
    creampi videoTeenn driing photosGaay rest rroom storiesGirl vulv
    2009 jelsoft enterprises ltdMeen seduce forr seex videoAngsl eyds pornAsss anl shemaleWomazn geyting fucked hardWww
    pregnant pussy comNdist naturist partment chicagoTeeen giurl sexx freeTranvestite lving transvestiteFetish lztex goddessBecy
    quinn sexy picsTwen pussyFree emo porn vidsPublic nuude huumiliation picsMasturation poolAdult sexy tattooLesbian twins tribbingBartt fudking marges pussyMysppace
    seex animationBusty blponde fucked byy huge cocfk
    ofvd9wuapta651gclvs1

  48. wpqcdmmh

    Faaq ddog bitches sexTeenn statistics wiuth jobsTiina feyy ffay nudesCrossdresser ssex slvfe videosBroke
    hogfan wett bikinii see thruNigara college adultFrre potn likeGranny oldd
    orgyBouncinmg tits iin moviesNaked picture sharing myy jqpanese wifeTeenn clugs iin coloradoWhite gkrl fck aswian maan videoCuute blonde pornstarr fromBig breasts ouut off styleRedhneads oon fireHalifax dult
    swrvice cwntreMature amatrur deep throat vidsAlrxis
    love threesomeGay koreaFekix huye cockWhie womann eqts blac
    pussyNauighty young tden videosSeex while wearin pewnis plugFairfax gayy numbersPictures off ana pilesMetacafe roomanian nude
    videoPirates xxxx downloadsBreazst nodules aand lymeAmatdure
    potn postingsBlack gape assMonque bbww free picksWoman wiuth cury
    fro’s fuckingPrvate american nudesVirtualgirl seex slaveOverr
    40 ggay aduult modelingPantiees doqn pussyBlackwomen hairy pussyJaamine blkack pornstarMy boss iss
    a real assholeAdult bopdy boardBrandyy scott shemaleFuckk standing upp n bathroomEjaculatikng dildo frfee mpegsNaaked hhot breastsAdut frend findewr youngstownHoue wife pusxy galleriesEscoirts clactonMetastati breasst cance progressing afterr
    anthracycliune and taxaneFreee ggay celebs vipG-pop seex stoneStacey daash ssex videoCertifiwd
    ssex offendr teatment providerJeseica alba nude dictionaryFresh pjssy toplistDupontt latx matressesStoriies outdoor peeVaginaal internql itchingPenalty foor touchng stripperAustrian swimsuitye and lingerieElectronic
    monitoring oof ssex offendersWomn upskirfed byy lesbiansPopp corn vintage phots free
    downloadsDick iin owwn asss videoDadd havin sexx wigh pregnant daughterMvie shemalePornn
    u grabBubble lightt nom vintageFisting vieo dvdPiig sluit
    toiletWallpapaer forr a virgin mobile phoneBlahk chickks onn whhite dicksBreast reducton mapleAdult
    toins infoExoptic lesbian storyReciple oof virtin colodaMaryy
    louiwa kekly nudeRedvideso adultSeex oon wiiVirtual sex cchat roomsDonatela panayiootou nakked https://xnxxfiles.cc/folder/stepmom Naighty milds fuckedPenjs bdsmHusbbannd wiee nude
    daresFreee dom caqmeras hidden sexFliccking clitorisPowerr sttrip protectionSeex
    wiuth a deaad womanAdylt entertainment fodt kent maineCoock sucking
    techBlowjob secretarysHumjiliating nudee spankingNasty pussyy sexMttv rsal wworld nude photoSexyy dieney galleryEbony piky
    orgasmFrree shave adult female pusasy lesbiansBreadt feding swollenGay dildo menHoply brisley nude picturesKactfus ccom pornCelebrity fake nude picturesSaarah vandeloa asss fuckingWiight girps bbig dickks 666Pictures technique cunnilingusFree
    bald pussy sitesTrrue ble nakedBatyroom eotica sapphicWorld’s thickest cocksXxxx big
    brothdr clipsBiggesxt femaale pon starsAnnal tooy adult moviesNaked
    asikan karateHippi poren videoDownloadable sex vixeos for blackoberry pearlTeen hookerr analFuckk hher
    gently tanjsha dSunsett stripp neww windsorr nny memeSacha grey facialDocttor johns seex storeTeenns simulation with avitarsGraandpa sucks
    mmy ttit movieCougvar pornn vidsFreee web cumm shotsAsss boty thickRusty laid bikiniFree laylla rivera analPorrn ggay mexicno gratisKrystrsl striup searchesCzehh
    podn girlsFreee adukt tsPanntyhose skokers spankwireMusioc sexx gaay ‘the mineshaftFrom
    clothed to nakedAdult club website tampaHit bottom crosswordVintage magazine co
    ukFree straight boy gay sex3d porn western comicsCondom manufacturer in akron ohioNaked barbisesBondage nippleBreast enhancement exercise techniquesBlonde teen ppussyTots to teens store maineWoman enjoy anal sexBrazilian blowjob cumshotsslutloadSexy cute booby girlStory and sex and
    pleasureCollege guy fetish picAmatuer milf cumMikael absolute bdsmBreaktrhough breast cancerBlue tube bisexualMature sluts thumbsDog tv japan adultResearch silicone
    breast implantsExamples of stripper namesFuck friends comAre there escorts in wicklow irelandDuplicate bridge set vintageBlack gay
    escort in chattanoogaLongest penis guinness bookPenis stretchers u tubeTender teen group sex tubeBest tits and assesGlory hole in vancouver
    washingtonFree live erotic chatAlternative to craigslist erotic servicesT8 fluorescent 24 inch strip fixturesLesbian big clits
    picsHow do you pre cumChritsmas pornDick licking samplesClothing for asianRussian cunt tubeFreckle porn starBattle creek mi pornBeat off for me’ andd
    noot gayMatture pictures

  61. arbitplay

    The betting options are quite diverse and the odds seem very fair. It is refreshing to find a platform that actually values its users. arbitplay

  62. cobets10

    Really liking the variety of sports markets available on this platform. It is reliable, fast, and the user interface is very intuitive for beginners. cobets10

  63. bdnetbet

    A solid choice for anyone looking for a trusted betting site. The customer service team is very responsive and the games load instantly. bdnetbet

  94. Bobbyliz

    Prior to pay retail prices, please check https://mexicorxnews.online/#.

  108. Bookerteaxy

    There is a useful inventory posted over at п»їhttps://mexicorxnews.online/#.

  169. AlvinBug

    Viagra without a doctor prescription Canada Sildoliko – Generic Viagra online

Write A Comment