{"id":31333,"date":"2019-10-31T21:40:44","date_gmt":"2019-10-31T18:40:44","guid":{"rendered":"https:\/\/prohoster.info\/blog\/virtualnye-fajlovye-sistemy-v-linux-zachem-oni-nuzhny-i-kak-oni-rabotayut-chast-2\/"},"modified":"2019-10-31T21:40:44","modified_gmt":"2019-10-31T18:40:44","slug":"virtualnye-fajlovye-sistemy-v-linux-zachem-oni-nuzhny-i-kak-oni-rabotayut-chast-2","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/administrirovanie\/virtualnye-fajlovye-sistemy-v-linux-zachem-oni-nuzhny-i-kak-oni-rabotayut-chast-2","title":{"rendered":"Virtu\u00e1ln\u00ed souborov\u00e9 syst\u00e9my v Linuxu: k \u010demu slou\u017e\u00ed a jak funguj\u00ed? \u010c\u00e1st 2","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Ahoj v\u0161em, sd\u00edl\u00edme s v\u00e1mi druhou \u010d\u00e1st publikace \u201eVirtu\u00e1ln\u00ed souborov\u00e9 syst\u00e9my v Linuxu: k \u010demu jsou a jak funguj\u00ed?\u201c Prvn\u00ed \u010d\u00e1st si m\u016f\u017eete p\u0159e\u010d\u00edst tady<\/a><\/noindex>. P\u0159ipom\u00edn\u00e1me, \u017ee tato s\u00e9rie publikac\u00ed je v\u011bnov\u00e1na spu\u0161t\u011bn\u00ed nov\u00e9ho cyklu kurzu \u201eLinuxov\u00fd administr\u00e1tor\u201c<\/a><\/noindex>, kter\u00fd ji\u017e brzy za\u010dne.<\/p>\n

Jak sledovat VFS pomoc\u00ed n\u00e1stroj\u016f eBPF a bcc<\/b><\/p>\n

Nejjednodu\u0161\u0161\u00ed zp\u016fsob, jak pochopit, jak j\u00e1dro manipuluje s soubory sysfs<\/code> \u2013 je pozorovat to v praxi, a nejb\u011b\u017en\u011bj\u0161\u00ed zp\u016fsob, jak sledovat ARM64 \u2013 je pou\u017e\u00edt eBPF. eBPF (zkr\u00e1cen\u011b od Berkeley Packet Filter) se skl\u00e1d\u00e1 z virtu\u00e1ln\u00ed stroje spu\u0161t\u011bn\u00e9ho v j\u00e1d\u0159e<\/a><\/noindex>, jeho\u017e privilegovan\u00ed u\u017eivatel\u00e9 mohou dotazovat (query<\/code>) z p\u0159\u00edkazov\u00e9ho \u0159\u00e1dku. Zdrojov\u00e9 k\u00f3dy j\u00e1dra informuj\u00ed \u010dten\u00e1\u0159e, co j\u00e1dro m\u016f\u017ee prov\u00e1d\u011bt; spu\u0161t\u011bn\u00ed n\u00e1stroj\u016f eBPF v provozovan\u00e9m syst\u00e9mu ukazuje, co j\u00e1dro skute\u010dn\u011b d\u011bl\u00e1. <\/p>\n

\"Virtu\u00e1ln\u00ed<\/a><\/noindex><\/p>\n

Na\u0161t\u011bst\u00ed je za\u010d\u00edt pou\u017e\u00edvat eBPF pom\u011brn\u011b jednoduch\u00e9 pomoc\u00ed n\u00e1stroj\u016f bcc<\/a><\/noindex>, kter\u00e9 jsou dostupn\u00e9 jako bal\u00ed\u010dky z b\u011b\u017en\u00e9 distribuce Linux<\/a><\/noindex> a jsou podrobn\u011b zdokumentov\u00e1ny Bernardem Greggem<\/a><\/noindex>. N\u00e1stroje bcc<\/code> \u2013 jsou skripty v Pythonu s mal\u00fdmi vlo\u017ekami k\u00f3du v C, co\u017e znamen\u00e1, \u017ee ka\u017ed\u00fd, kdo zn\u00e1 oba jazyky, je m\u016f\u017ee snadno upravit. V bcc\/tools<\/code> je 80 skript\u016f v Pythonu, co\u017e znamen\u00e1, \u017ee pravd\u011bpodobn\u011b v\u00fdvoj\u00e1\u0159 nebo syst\u00e9mov\u00fd administr\u00e1tor najde n\u011bco vhodn\u00e9ho k vy\u0159e\u0161en\u00ed \u00fakolu.
\nAbychom z\u00edskali alespo\u0148 povrchovou p\u0159edstavu o tom, jakou pr\u00e1ci vykon\u00e1vaj\u00ed VFS v provozovan\u00e9m syst\u00e9mu, zkuste vfscount<\/code> nebo vfsstat<\/code>. To uk\u00e1\u017ee, \u017ee nap\u0159\u00edklad deset v\u00fdzev vfs_open()<\/code> a jeho \u201ep\u0159\u00e1tel\u201c se odehr\u00e1v\u00e1 doslova ka\u017edou sekundu.<\/p>\n

\"Virtu\u00e1ln\u00ed
\n<\/p>\n

vfsstat.py<\/code> \u2013 je skript v Pythonu, se vlo\u017ekami C k\u00f3du, kter\u00fd jednodu\u0161e po\u010d\u00edt\u00e1 vol\u00e1n\u00ed funkc\u00ed VFS.<\/p><\/blockquote>\n

Uve\u010fme trivi\u00e1ln\u011bj\u0161\u00ed p\u0159\u00edklad a pod\u00edvejme se, co se stane, kdy\u017e p\u0159ipoj\u00edme USB flash disk k po\u010d\u00edta\u010di a syst\u00e9m ho zaznamen\u00e1.<\/p>\n

\"Virtu\u00e1ln\u00ed
\n<\/p>\n

Pomoc\u00ed eBPF m\u016f\u017eeme zjistit, co se d\u011bje v \/sys<\/code>, kdy\u017e je p\u0159ipojen USB flash disk. Zde je jednoduch\u00fd a slo\u017eit\u00fd p\u0159\u00edklad.<\/p><\/blockquote>\n

V p\u0159\u00edkladu uveden\u00e9m naho\u0159e, bcc<\/code> n\u00e1stroj trace.py<\/a><\/noindex> vytiskne zpr\u00e1vu, kdy\u017e je spu\u0161t\u011bna p\u0159\u00edkaz sysfs_create_files()<\/code>. Vid\u00edme, \u017ee sysfs_create_files()<\/code> byl spu\u0161t\u011bn pomoc\u00ed kworker<\/code> vl\u00e1kna v reakci na to, \u017ee byl disk p\u0159ipojen, ale jak\u00fd soubor byl v t\u00e9to souvislosti vytvo\u0159en? Druh\u00fd p\u0159\u00edklad ukazuje celou s\u00edlu eBPF. Zde trace.py<\/code> prov\u00e1d\u00ed zp\u011btn\u00e9 sledov\u00e1n\u00ed j\u00e1dra (kernel backtrace) (volba -K) a n\u00e1zev souboru, kter\u00fd byl vytvo\u0159en sysfs_create_files()<\/code>. Vlo\u017een\u00ed do jednotliv\u00fdch v\u00fdrok\u016f je k\u00f3d v C, kter\u00fd zahrnuje snadno rozpoznateln\u00fd form\u00e1tovac\u00ed \u0159et\u011bzec, zaji\u0161\u0165ovan\u00fd Python skriptem, kter\u00fd spou\u0161t\u00ed LLVM just-in-time kompil\u00e1tor<\/i>. Tento \u0159et\u011bzec se kompiluje a vykon\u00e1v\u00e1 ve virtu\u00e1ln\u00ed stroji uvnit\u0159 j\u00e1dra. Kompletn\u00ed signatura funkce sysfs_create_files ()<\/code> mus\u00ed b\u00fdt reprodukov\u00e1na ve druh\u00e9m p\u0159\u00edkazu, aby se form\u00e1tovac\u00ed \u0159et\u011bzec mohl odkazovat na jeden z parametr\u016f. Chyby v tomto \u00faseku k\u00f3du v C vedou k rozpoznateln\u00fdm chyb\u00e1m C kompil\u00e1toru. Nap\u0159\u00edklad, pokud je vynech\u00e1n parametr -l, uvid\u00edte \"Failed to compile BPF text.\" V\u00fdvoj\u00e1\u0159i, kte\u0159\u00ed jsou dob\u0159e obezn\u00e1meni s C a Python, najdou n\u00e1stroje bcc<\/code> snadn\u00e9 pro roz\u0161\u00ed\u0159en\u00ed a \u00fapravy.<\/p>\n

Kdy\u017e je USB disk vlo\u017een, zp\u011btn\u00e9 sledov\u00e1n\u00ed j\u00e1dra uk\u00e1\u017ee, \u017ee PID 7711 je vl\u00e1kno kworker<\/code>, kter\u00e9 vytvo\u0159ilo soubor \"events\"<\/code> v sysfs<\/code>. Odpov\u00eddaj\u00edc\u00ed vol\u00e1n\u00ed s sysfs_remove_files()<\/code> uk\u00e1\u017ee, \u017ee odstran\u011bn\u00ed disku vedlo k odstran\u011bn\u00ed souboru events<\/code>, co\u017e odpov\u00edd\u00e1 celkov\u00e9 koncepci po\u010d\u00edt\u00e1n\u00ed referenc\u00ed. P\u0159i tom, prohl\u00e9dnut\u00ed sysfs_create_link ()<\/code> s eBPF b\u011bhem vlo\u017een\u00ed USB disku uk\u00e1\u017ee, \u017ee bylo vytvo\u0159eno nejm\u00e9n\u011b 48 symbolick\u00fdch odkaz\u016f.<\/p>\n

Jak\u00fd je tedy smysl souboru events? Pou\u017eit\u00ed cscope<\/a><\/noindex> k vyhled\u00e1n\u00ed __device_add_disk()<\/a><\/noindex>, ukazuje, \u017ee vol\u00e1 disk_add_events ()<\/code>, a bu\u010f \"media_change\"<\/code>, nebo \"eject_request\"<\/code> mohou b\u00fdt zaps\u00e1ny do souboru ud\u00e1lost\u00ed. Zde blokov\u00e1 vrstva j\u00e1dra informuje userspace o p\u0159\u00edtomnosti a odstran\u011bn\u00ed \"disku\". V\u0161imn\u011bte si, jak informativn\u00ed je tato metoda zkoum\u00e1n\u00ed na p\u0159\u00edkladu vlo\u017een\u00ed USB disku v porovn\u00e1n\u00ed s pokusy zjistit, jak v\u0161e funguje, v\u00fdhradn\u011b z zdrojov\u00fdch k\u00f3d\u016f.<\/p>\n

Ko\u0159enov\u00e9 souborov\u00e9 syst\u00e9my pouze pro \u010dten\u00ed umo\u017e\u0148uj\u00ed vestav\u011bn\u00e1 za\u0159\u00edzen\u00ed<\/b><\/p>\n

Samoz\u0159ejm\u011b nikdo nevyp\u00edn\u00e1 server nebo sv\u016fj po\u010d\u00edta\u010d t\u00edm, \u017ee vyt\u00e1hne z\u00e1str\u010dku ze z\u00e1suvky. Ale pro\u010d? A to proto, \u017ee p\u0159ipojen\u00e9 souborov\u00e9 syst\u00e9my na fyzick\u00fdch za\u0159\u00edzen\u00edch ukl\u00e1d\u00e1n\u00ed mohou m\u00edt odlo\u017een\u00e9 z\u00e1pisy, a datov\u00e9 struktury, kter\u00e9 je ukl\u00e1daj\u00ed, se nemus\u00ed synchronizovat se z\u00e1pisy v \u00falo\u017ei\u0161ti. Kdy\u017e se to stane, majitel\u00e9 syst\u00e9mu mus\u00ed \u010dekat na p\u0159\u00ed\u0161t\u00ed spu\u0161t\u011bn\u00ed, aby spustili n\u00e1stroj fsck filesystem-recovery<\/code> a v nejhor\u0161\u00edm p\u0159\u00edpad\u011b ztratit data. <\/p>\n

Nicm\u00e9n\u011b, v\u0161ichni v\u00edme, \u017ee mnoho za\u0159\u00edzen\u00ed IoT, jako\u017e i sm\u011brova\u010de, termostaty a automobily nyn\u00ed b\u011b\u017e\u00ed na Linuxu. Mnoh\u00e1 z t\u011bchto za\u0159\u00edzen\u00ed prakticky nemaj\u00ed u\u017eivatelsk\u00e9 rozhran\u00ed a nen\u00ed \u017e\u00e1dn\u00fd zp\u016fsob, jak je \u201e\u010dist\u011b\u201c vypnout. P\u0159edstavte si spu\u0161t\u011bn\u00ed auta s vybitou bateri\u00ed, kdy\u017e se nap\u00e1jen\u00ed \u0159\u00eddic\u00edho za\u0159\u00edzen\u00ed neust\u00e1le m\u011bn\u00ed. Linux<\/a><\/noindex> Jak je mo\u017en\u00e9, \u017ee syst\u00e9m se spust\u00ed bez dlouh\u00e9ho fsck<\/code>, kdy\u017e motor kone\u010dn\u011b za\u010dne b\u011b\u017eet? Odpov\u011b\u010f je jednoduch\u00e1. Vestav\u011bn\u00e1 za\u0159\u00edzen\u00ed se spol\u00e9haj\u00ed na ko\u0159enov\u00fd souborov\u00fd syst\u00e9m pouze pro \u010dten\u00ed<\/a><\/noindex> (zkr\u00e1cen\u011b ro-rootfs<\/code> (read-only root fileystem)). <\/p>\n

ro-rootfs<\/code> Nab\u00edzej\u00ed mnoho v\u00fdhod, kter\u00e9 jsou m\u00e9n\u011b z\u0159ejm\u00e9 ne\u017e nefal\u0161ovanost. Jedna z v\u00fdhod spo\u010d\u00edv\u00e1 v tom, \u017ee \u0161kodliv\u00fd software nem\u016f\u017ee zapisovat do \/usr<\/code> nebo \/lib<\/code>, pokud \u017e\u00e1dn\u00fd proces Linuxu do n\u011bj nem\u016f\u017ee zapisovat. Dal\u0161\u00ed spo\u010d\u00edv\u00e1 v tom, \u017ee do zna\u010dn\u00e9 m\u00edry nem\u011bnn\u00fd souborov\u00fd syst\u00e9m je kl\u00ed\u010dov\u00fd pro support vzd\u00e1len\u00fdch za\u0159\u00edzen\u00ed, proto\u017ee pomocn\u00fd person\u00e1l pou\u017e\u00edv\u00e1 m\u00edstn\u00ed syst\u00e9my, kter\u00e9 jsou nomin\u00e1ln\u011b identick\u00e9 s syst\u00e9my na m\u00edst\u011b. Mo\u017en\u00e1 nejd\u016fle\u017eit\u011bj\u0161\u00ed (ale tak\u00e9 nejz\u00e1ludn\u011bj\u0161\u00ed) v\u00fdhodou je, \u017ee ro-rootfs nut\u00ed v\u00fdvoj\u00e1\u0159e rozhodnout, kter\u00e9 syst\u00e9mov\u00e9 objekty budou nem\u011bnn\u00e9, je\u0161t\u011b v dob\u011b navrhov\u00e1n\u00ed syst\u00e9mu. Pr\u00e1ce s ro-rootfs m\u016f\u017ee b\u00fdt nepr\u00edjemn\u00e1 a bolestiv\u00e1, jak to \u010dasto b\u00fdv\u00e1 s prom\u011bnn\u00fdmi const v programovac\u00edch jazyk\u00e1ch, ale jejich v\u00fdhody snadno p\u0159ev\u00e1\u017e\u00ed dodate\u010dn\u00e9 n\u00e1klady.<\/p>\n

Tvorba rootfs<\/code> Pouze pro \u010dten\u00ed vy\u017eaduje ur\u010dit\u00e9 dal\u0161\u00ed \u00fasil\u00ed od v\u00fdvoj\u00e1\u0159\u016f vestav\u011bn\u00fdch syst\u00e9m\u016f, a pr\u00e1v\u011b zde p\u0159ich\u00e1z\u00ed VFS do hry. Linux vy\u017eaduje, aby soubory v \/var<\/code> byly dostupn\u00e9 pro z\u00e1pis, a nav\u00edc mnoh\u00e9 popul\u00e1rn\u00ed aplikace, kter\u00e9 spou\u0161t\u00ed vestav\u011bn\u00e9 syst\u00e9my, se pokus\u00ed vytvo\u0159it konfigura\u010dn\u00ed dot-files<\/code> v $HOME<\/code>. Jedn\u00edm z \u0159e\u0161en\u00ed pro konfigura\u010dn\u00ed soubory v dom\u00e1c\u00edm adres\u00e1\u0159i je obvykle jejich p\u0159edb\u011b\u017en\u00e9 vygenerov\u00e1n\u00ed a sestaven\u00ed do rootfs<\/code>. Pro \/var<\/code> Jedn\u00edm z mo\u017en\u00fdch p\u0159\u00edstup\u016f je namontovat je na samostatnou partition, kter\u00e1 je dostupn\u00e1 pro z\u00e1pis, zat\u00edmco samotn\u00fd \/<\/code> je namontov\u00e1n pouze pro \u010dten\u00ed. Dal\u0161\u00ed popul\u00e1rn\u00ed alternativou je pou\u017eit\u00ed propojen\u00fdch nebo p\u0159ekr\u00fdvaj\u00edc\u00edch se mont\u00e1\u017e\u00ed (bind or overlay mounts).<\/p>\n

Sv\u00e1zan\u00e9 a p\u0159ekryt\u00e9 mont\u00e1\u017ee, jejich pou\u017eit\u00ed kontejnery<\/b> <\/p>\n

Proveden\u00ed p\u0159\u00edkazu man mount<\/code> je nejlep\u0161\u00ed zp\u016fsob, jak se sezn\u00e1mit se sv\u00e1zan\u00fdmi a p\u0159ekryt\u00fdmi mont\u00e1\u017eemi, kter\u00e9 umo\u017e\u0148uj\u00ed v\u00fdvoj\u00e1\u0159\u016fm a syst\u00e9mov\u00fdm administr\u00e1tor\u016fm vytv\u00e1\u0159et souborov\u00fd syst\u00e9m na jedn\u00e9 cest\u011b a pot\u00e9 jej poskytovat aplikac\u00edm na jin\u00e9. Pro vestav\u011bn\u00e9 syst\u00e9my to znamen\u00e1 mo\u017enost uchov\u00e1vat soubory na \/var<\/code> flash disku, kter\u00fd je dostupn\u00fd pouze pro \u010dten\u00ed, ale p\u0159ekryt\u00ed nebo sv\u00e1z\u00e1n\u00ed mont\u00e1\u017ee cesty z tmpfs<\/code> v \/var<\/code> p\u0159i spu\u0161t\u011bn\u00ed umo\u017en\u00ed aplikac\u00edm zapisovat pozn\u00e1mky. P\u0159i dal\u0161\u00edm zapnut\u00ed budou zm\u011bny v \/var<\/code> ztraceny. P\u0159ekryt\u00e1 mont\u00e1\u017e vytv\u00e1\u0159\u00ed spojen\u00ed mezi tmpfs<\/code> a podkladov\u00fdm souborov\u00fdm syst\u00e9mem a umo\u017e\u0148uje \u00fadajn\u00e9 zm\u011bny existuj\u00edc\u00edch soubor\u016f v ro-tootf<\/code> zat\u00edmco sv\u00e1zan\u00e1 mont\u00e1\u017e m\u016f\u017ee ud\u011blat nov\u00e9 pr\u00e1zdn\u00e9 tmpfs<\/code> adres\u00e1\u0159e viditeln\u00e9 jako dostupn\u00e9 pro z\u00e1pis v ro-rootfs<\/code> cest\u00e1ch. Zat\u00edmco overlayfs<\/code> je spr\u00e1vn\u00fd (proper<\/code>) typ souborov\u00e9ho syst\u00e9mu, sv\u00e1zan\u00e1 mont\u00e1\u017e je realizov\u00e1na v rozhran\u00ed VFS<\/a><\/noindex>.<\/p>\n

Na z\u00e1klad\u011b popisu p\u0159ekryt\u00ed a sv\u00e1z\u00e1n\u00ed mont\u00e1\u017ee se nikdo nediv\u00ed, \u017ee Linux kontejnery<\/a><\/noindex> je aktivn\u011b vyu\u017e\u00edvaj\u00ed. Poj\u010fme pozorovat, co se stane, kdy\u017e pou\u017eijeme systemd-nspawn<\/a><\/noindex> k spu\u0161t\u011bn\u00ed kontejneru, pou\u017e\u00edvaj\u00edc\u00ed n\u00e1stroj mountsnoop<\/code> od bcc<\/code>.<\/p>\n

Zavol\u00e1n\u00ed system-nspawn<\/code> spou\u0161t\u00ed kontejner b\u011bhem pr\u00e1ce mountsnoop.py<\/code>.<\/p>\n

Pod\u00edvejme se, co se stalo:<\/p>\n

Spu\u0161t\u011bn\u00ed mountsnoop<\/code> b\u011bhem \"na\u010d\u00edt\u00e1n\u00ed\" kontejneru ukazuje, \u017ee b\u011bhov\u00e9 prost\u0159ed\u00ed kontejneru siln\u011b z\u00e1vis\u00ed na sv\u00e1zan\u00e9 mont\u00e1\u017ei (Zobrazen pouze za\u010d\u00e1tek dlouh\u00e9ho v\u00fdstupu).<\/p>\n

Zde systemd-nspawn<\/code> poskytuje vybran\u00e9 soubory v procfs<\/code> a sysfs<\/code> hosta do kontejneru jako cesty v jeho rootfs<\/code>. Krom\u011b MS_BIND<\/code> flag, kter\u00fd nastavuje sv\u00e1zanou mont\u00e1\u017e, existuj\u00ed v montovan\u00e9m syst\u00e9mu n\u011bkter\u00e9 dal\u0161\u00ed flagy, kter\u00e9 ur\u010duj\u00ed vztah mezi zm\u011bnami v prostoru n\u00e1zv\u016f hostitele a kontejneru. Nap\u0159\u00edklad sv\u00e1zan\u00e1 mont\u00e1\u017e m\u016f\u017ee bu\u010f propustit zm\u011bny do \/proc<\/code> a \/sys<\/code> kontejneru, nebo je skr\u00fdt v z\u00e1vislosti na vol\u00e1n\u00ed. <\/p>\n

Z\u00e1v\u011br<\/b><\/p>\n

Pochopen\u00ed vnit\u0159n\u00ed struktury Linuxu se m\u016f\u017ee zd\u00e1t jako nesplniteln\u00fd \u00fakol, proto\u017ee j\u00e1dro samo obsahuje obrovsk\u00e9 mno\u017estv\u00ed k\u00f3du, ani\u017e by se braly v \u00favahu aplikace u\u017eivatelsk\u00e9ho prostoru Linuxu a rozhran\u00ed syst\u00e9mov\u00fdch vol\u00e1n\u00ed v knihovn\u00e1ch jazyka C, jako jsou glibc<\/code>. Jedn\u00edm ze zp\u016fsob\u016f, jak dos\u00e1hnout pokroku, je p\u0159e\u010d\u00edst si zdrojov\u00fd k\u00f3d jedn\u00e9 podsyst\u00e9my j\u00e1dra se zam\u011b\u0159en\u00edm na pochopen\u00ed syst\u00e9mov\u00fdch vol\u00e1n\u00ed a hlavi\u010dek, kter\u00e9 se t\u00fdkaj\u00ed prostoru u\u017eivatele, jako\u017e i z\u00e1kladn\u00edch vnit\u0159n\u00edch rozhran\u00ed j\u00e1dra, nap\u0159\u00edklad tabulka file_operations<\/code>. Operace se soubory zaji\u0161\u0165uj\u00ed princip \u201ev\u0161echno je soubor\u201c, tak\u017ee jejich spr\u00e1va je obzvl\u00e1\u0161\u0165 p\u0159\u00edjemn\u00e1. Zdrojov\u00e9 soubory j\u00e1dra v jazyce C se nach\u00e1zej\u00ed v z\u00e1kladn\u00edm adres\u00e1\u0159i fs\/<\/code> p\u0159edstavuj\u00ed implementaci virtu\u00e1ln\u00edch souborov\u00fdch syst\u00e9m\u016f, kter\u00e9 tvo\u0159\u00ed vrstvu obalu zaji\u0161\u0165uj\u00edc\u00ed \u0161irokou a relativn\u011b jednoduchou kompatibilitu popul\u00e1rn\u00edch souborov\u00fdch syst\u00e9m\u016f a \u00falo\u017en\u00fdch za\u0159\u00edzen\u00ed. P\u0159ipojov\u00e1n\u00ed s vazbou a p\u0159ekr\u00fdv\u00e1n\u00ed prost\u0159ednictv\u00edm jmenn\u00fdch prostor\u016f syst\u00e9mu Linux je kouzlo VFS, kter\u00e9 umo\u017e\u0148uje vytv\u00e1\u0159en\u00ed kontejner\u016f a ko\u0159enov\u00fdch souborov\u00fdch syst\u00e9m\u016f pouze pro \u010dten\u00ed. V kombinaci se studiem zdrojov\u00e9ho k\u00f3du, j\u00e1drov\u00fdm n\u00e1strojem eBPF a jeho rozhran\u00edm bcc<\/code>
\n u\u010din\u00ed v\u00fdzkum j\u00e1dra snadn\u011bj\u0161\u00edm ne\u017e kdy d\u0159\u00edve.<\/p>\n

P\u0159\u00e1tel\u00e9, napi\u0161te, zda v\u00e1m tento \u010dl\u00e1nek byl u\u017eite\u010dn\u00fd. Mo\u017en\u00e1 m\u00e1te n\u011bjak\u00e9 koment\u00e1\u0159e nebo pozn\u00e1mky? A ty, kter\u00e9 zaj\u00edm\u00e1 kurz \u201eAdministr\u00e1tor Linux\u201c, zveme na den otev\u0159en\u00fdch dve\u0159\u00ed<\/a><\/noindex>, kter\u00fd prob\u011bhne 18. dubna.<\/p>\n

Prvn\u00ed \u010d\u00e1st.<\/a><\/noindex>
\n
Zdroj: habr.com<\/a><\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

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