{"id":5059,"date":"2026-11-01T10:52:40","date_gmt":"2026-11-01T10:52:40","guid":{"rendered":"https:\/\/zynoo.com\/blog\/502-bad-gateway-nginx\/"},"modified":"2026-11-01T16:27:30","modified_gmt":"2026-11-01T16:27:30","slug":"502-bad-gateway-nginx","status":"publish","type":"post","link":"https:\/\/zynoo.com\/blog\/vi\/502-bad-gateway-nginx\/","title":{"rendered":"C\u00e1ch kh\u1eafc ph\u1ee5c l\u1ed7i 502 Bad Gateway trong Nginx (t\u1eebng b\u01b0\u1edbc)"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\" id=\"h-\"><strong>L\u1ed7i 502 Bad Gateway trong Nginx<\/strong> th\u01b0\u1eddng c\u00f3 ngh\u0129a l\u00e0 Nginx kh\u00f4ng nh\u1eadn \u0111\u01b0\u1ee3c ph\u1ea3n h\u1ed3i h\u1ee3p l\u1ec7 t\u1eeb m\u00e1y ch\u1ee7 th\u01b0\u1ee3ng ngu\u1ed3n, ch\u1eb3ng h\u1ea1n nh\u01b0 PHP-FPM, Node.js ho\u1eb7c m\u1ed9t \u1ee9ng d\u1ee5ng backend kh\u00e1c.<\/p>\n\n<p class=\"wp-block-paragraph\">Nh\u1eefng nguy\u00ean nh\u00e2n ph\u1ed5 bi\u1ebfn nh\u1ea5t l\u00e0 d\u1ecbch v\u1ee5 \u1ee9ng d\u1ee5ng \u0111\u00e3 d\u1eebng, c\u1ed5ng ho\u1eb7c socket th\u01b0\u1ee3ng ngu\u1ed3n \u0111\u01b0\u1ee3c c\u1ea5u h\u00ecnh sai, v\u00e0 ti\u1ebfn tr\u00ecnh backend g\u1eb7p s\u1ef1 c\u1ed1 ho\u1eb7c \u0111\u00f3ng k\u1ebft n\u1ed1i \u0111\u1ed9t ng\u1ed9t.<\/p>\n\n<p class=\"wp-block-paragraph\"><strong>Tr\u01b0\u1edbc ti\u00ean, h\u00e3y ki\u1ec3m tra nh\u1eadt k\u00fd l\u1ed7i c\u1ee7a Nginx.<\/strong> Ch\u00fang th\u01b0\u1eddng cho bi\u1ebft ch\u00ednh x\u00e1c l\u00fd do k\u1ebft n\u1ed1i th\u1ea5t b\u1ea1i.<\/p>\n\n<p class=\"wp-block-paragraph\">H\u01b0\u1edbng d\u1eabn n\u00e0y tr\u00ecnh b\u00e0y b\u1ea3y b\u01b0\u1edbc thi\u1ebft th\u1ef1c \u0111\u1ec3 ch\u1ea9n \u0111o\u00e1n v\u00e0 kh\u1eafc ph\u1ee5c s\u1ef1 c\u1ed1 tr\u00ean m\u00e1y ch\u1ee7 Linux ch\u1ea1y Nginx.<\/p>\n\n<h2 id=\"h-what-causes-a-502-bad-gateway-error-in-nginx\" class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Nguyen_nhan_nao_gay_ra_loi_502_Bad_Gateway_trong_Nginx\"><\/span>Nguy\u00ean nh\u00e2n n\u00e0o g\u00e2y ra l\u1ed7i 502 Bad Gateway trong Nginx?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n<p class=\"wp-block-paragraph\">Nginx th\u01b0\u1eddng \u0111\u00f3ng vai tr\u00f2 proxy ng\u01b0\u1ee3c, chuy\u1ec3n ti\u1ebfp y\u00eau c\u1ea7u \u0111\u1ebfn c\u00e1c \u1ee9ng d\u1ee5ng backend r\u1ed3i tr\u1ea3 ph\u1ea3n h\u1ed3i c\u1ee7a ch\u00fang cho ng\u01b0\u1eddi truy c\u1eadp.<\/p>\n\n<p class=\"wp-block-paragraph\">N\u1ebfu d\u1ecbch v\u1ee5 th\u01b0\u1ee3ng ngu\u1ed3n kh\u00f4ng ph\u1ea3n h\u1ed3i \u0111\u00fang c\u00e1ch, Nginx c\u00f3 th\u1ec3 tr\u1ea3 v\u1ec1 m\u00e3 tr\u1ea1ng th\u00e1i HTTP 502.<\/p>\n\n<p class=\"wp-block-paragraph\">C\u00e1c nguy\u00ean nh\u00e2n ph\u1ed5 bi\u1ebfn bao g\u1ed3m:<\/p>\n\n<ul class=\"wp-block-list\">\n<li>D\u1ecbch v\u1ee5 backend \u0111\u00e3 d\u1eebng ho\u1eb7c g\u1eb7p s\u1ef1 c\u1ed1.<\/li>\n\n\n\n<li>\u0110\u1ecba ch\u1ec9 IP, c\u1ed5ng ho\u1eb7c socket Unix th\u01b0\u1ee3ng ngu\u1ed3n kh\u00f4ng ch\u00ednh x\u00e1c.<\/li>\n\n\n\n<li>Ti\u1ebfn tr\u00ecnh PHP-FPM ho\u1eb7c \u1ee9ng d\u1ee5ng g\u1eb7p s\u1ef1 c\u1ed1.<\/li>\n\n\n\n<li>V\u1ea5n \u0111\u1ec1 v\u1ec1 quy\u1ec1n truy c\u1eadp socket.<\/li>\n\n\n\n<li>Kh\u00f4ng \u0111\u1ee7 b\u1ed9 nh\u1edb ho\u1eb7c dung l\u01b0\u1ee3ng \u1ed5 \u0111\u0129a.<\/li>\n\n\n\n<li>K\u1ebft n\u1ed1i th\u01b0\u1ee3ng ngu\u1ed3n kh\u00f4ng h\u1ee3p l\u1ec7 ho\u1eb7c b\u1ecb \u0111\u00f3ng qu\u00e1 s\u1edbm.<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">C\u00e1c b\u01b0\u1edbc ki\u1ec3m tra sau \u0111\u00e2y gi\u1ea3 \u0111\u1ecbnh r\u1eb1ng b\u1ea1n c\u00f3 quy\u1ec1n truy c\u1eadp SSH v\u00e0 quy\u1ec1n qu\u1ea3n tr\u1ecb m\u00e1y ch\u1ee7 Linux c\u1ee7a m\u00ecnh.<\/p>\n\n<div class=\"wp-block-group zynoo-related-reading has-border-color has-text-color has-background is-layout-flow wp-block-group-is-layout-flow\" style=\"border-color:#c7d8ef;border-width:1px;border-radius:8px;border-left-color:#0069ff;border-left-width:3px;color:#24364f;background-color:#eaf2ff;margin-top:28px;margin-bottom:28px;padding-top:18px;padding-right:22px;padding-bottom:18px;padding-left:22px;font-size:16px;line-height:1.8\">\n<p class=\"wp-block-paragraph\"><strong>N\u1ebfu b\u1ea1n ch\u01b0a quen v\u1edbi vi\u1ec7c truy c\u1eadp m\u00e1y ch\u1ee7 t\u1eeb xa,<\/strong> h\u00e3y \u0111\u1ecdc <a href=\"https:\/\/zynoo.com\/blog\/vi\/ssh-commands\/\">h\u01b0\u1edbng d\u1eabn l\u1ec7nh SSH d\u00e0nh cho ng\u01b0\u1eddi m\u1edbi b\u1eaft \u0111\u1ea7u<\/a> c\u1ee7a ch\u00fang t\u00f4i tr\u01b0\u1edbc khi ti\u1ebfp t\u1ee5c.<\/p>\n<\/div>\n\n<figure class=\"wp-block-image size-large\"><img fetchpriority=\"high\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/zynoo.com\/blog\/wp-content\/uploads\/2026\/11\/what-cause-502-Bad-Gateway-Nginx-1024x576.webp\" alt=\"nguy&#xEA;n nh&#xE2;n g&#xE2;y l&#x1ED7;i 502 Bad Gateway trong Nginx\" class=\"wp-image-5037\" srcset=\"https:\/\/zynoo.com\/blog\/wp-content\/uploads\/2026\/11\/what-cause-502-Bad-Gateway-Nginx-1024x576.webp 1024w, https:\/\/zynoo.com\/blog\/wp-content\/uploads\/2026\/11\/what-cause-502-Bad-Gateway-Nginx-300x169.webp 300w, https:\/\/zynoo.com\/blog\/wp-content\/uploads\/2026\/11\/what-cause-502-Bad-Gateway-Nginx-768x432.webp 768w, https:\/\/zynoo.com\/blog\/wp-content\/uploads\/2026\/11\/what-cause-502-Bad-Gateway-Nginx-1536x864.webp 1536w, https:\/\/zynoo.com\/blog\/wp-content\/uploads\/2026\/11\/what-cause-502-Bad-Gateway-Nginx.webp 1672w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n<h2 id=\"h-1-check-the-nginx-error-logs\" class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"1_Kiem_tra_nhat_ky_loi_cua_Nginx\"><\/span>1. Ki\u1ec3m tra nh\u1eadt k\u00fd l\u1ed7i c\u1ee7a Nginx<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n<p class=\"wp-block-paragraph\">Nh\u1eadt k\u00fd l\u1ed7i c\u1ee7a Nginx th\u01b0\u1eddng l\u00e0 c\u00e1ch nhanh nh\u1ea5t \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh nguy\u00ean nh\u00e2n g\u00e2y l\u1ed7i 502.<\/p>\n\n<p class=\"wp-block-paragraph\">K\u1ebft n\u1ed1i v\u1edbi m\u00e1y ch\u1ee7 qua SSH v\u00e0 ch\u1ea1y:<\/p>\n\n<pre class=\"wp-block-code\"><code>sudo tail -n 50 \/var\/log\/nginx\/error.log<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">Thao t\u00e1c n\u00e0y hi\u1ec3n th\u1ecb 50 m\u1ee5c nh\u1eadt k\u00fd m\u1edbi nh\u1ea5t.<\/p>\n\n<p class=\"wp-block-paragraph\">\u0110\u1ec3 theo d\u00f5i khi ch\u1ea9n \u0111o\u00e1n s\u1ef1 c\u1ed1, h\u00e3y d\u00f9ng:<\/p>\n\n<pre class=\"wp-block-code\"><code>sudo tail -f \/var\/log\/nginx\/error.log<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">T\u1ea3i l\u1ea1i trang web b\u1ecb \u1ea3nh h\u01b0\u1edfng v\u00e0 theo d\u00f5i c\u00e1c th\u00f4ng b\u00e1o m\u1edbi.<\/p>\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><th>Th\u00f4ng b\u00e1o trong nh\u1eadt k\u00fd<\/th><th>Nguy\u00ean nh\u00e2n c\u00f3 th\u1ec3 x\u1ea3y ra<\/th><\/tr><tr><td><code>connect() failed (111: Connection refused)<\/code><\/td><td>Backend kh\u00f4ng ch\u1ea5p nh\u1eadn k\u1ebft n\u1ed1i<\/td><\/tr><tr><td><code>No such file or directory<\/code><\/td><td>Kh\u00f4ng t\u00ecm th\u1ea5y socket th\u01b0\u1ee3ng ngu\u1ed3n \u0111\u00e3 c\u1ea5u h\u00ecnh<\/td><\/tr><tr><td><code>Permission denied<\/code><\/td><td>Nginx kh\u00f4ng th\u1ec3 truy c\u1eadp socket ho\u1eb7c t\u00e0i nguy\u00ean<\/td><\/tr><tr><td><code>upstream prematurely closed connection<\/code><\/td><td>Backend \u0111\u00f3ng k\u1ebft n\u1ed1i \u0111\u1ed9t ng\u1ed9t<\/td><\/tr><tr><td><code>upstream sent invalid header<\/code><\/td><td>Backend tr\u1ea3 v\u1ec1 c\u00e1c header ph\u1ea3n h\u1ed3i kh\u00f4ng \u0111\u00fang \u0111\u1ecbnh d\u1ea1ng<\/td><\/tr><\/tbody><\/table><\/figure>\n\n<p class=\"wp-block-paragraph\">C\u1ea5u h\u00ecnh d\u1ecbch v\u1ee5 l\u01b0u tr\u1eef c\u1ee7a b\u1ea1n c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng v\u1ecb tr\u00ed nh\u1eadt k\u00fd kh\u00e1c.<\/p>\n\n<p class=\"wp-block-paragraph\"><strong>\u0110\u1eebng thay \u0111\u1ed5i c\u00e0i \u0111\u1eb7t Nginx cho \u0111\u1ebfn khi b\u1ea1n x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c nguy\u00ean nh\u00e2n c\u00f3 th\u1ec3 x\u1ea3y ra.<\/strong><\/p>\n\n<h2 id=\"h-2-check-whether-the-backend-service-is-running\" class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"2_Kiem_tra_xem_dich_vu_backend_co_dang_chay_khong\"><\/span>2. Ki\u1ec3m tra xem d\u1ecbch v\u1ee5 backend c\u00f3 \u0111ang ch\u1ea1y kh\u00f4ng<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n<p class=\"wp-block-paragraph\">L\u1ed7i 502 th\u01b0\u1eddng x\u1ea3y ra do \u1ee9ng d\u1ee5ng ch\u1ea1y ph\u00eda sau Nginx \u0111\u00e3 d\u1eebng.<\/p>\n\n<p class=\"wp-block-paragraph\">\u0110\u1ed1i v\u1edbi d\u1ecbch v\u1ee5 \u1ee9ng d\u1ee5ng do systemd qu\u1ea3n l\u00fd, h\u00e3y ch\u1ea1y:<\/p>\n\n<pre class=\"wp-block-code\"><code>sudo systemctl status myapp<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">Thay <code>myapp<\/code> b\u1eb1ng t\u00ean d\u1ecbch v\u1ee5 th\u1ef1c t\u1ebf c\u1ee7a b\u1ea1n.<\/p>\n\n<p class=\"wp-block-paragraph\">\u0110\u1ed1i v\u1edbi \u1ee9ng d\u1ee5ng d\u1ef1a tr\u00ean PHP s\u1eed d\u1ee5ng PHP-FPM, t\u00ean d\u1ecbch v\u1ee5 c\u00f3 th\u1ec3 c\u00f3 d\u1ea1ng:<\/p>\n\n<pre class=\"wp-block-code\"><code>sudo systemctl status php8.3-fpm<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">Phi\u00ean b\u1ea3n PHP \u0111\u00e3 c\u00e0i \u0111\u1eb7t v\u00e0 t\u00ean d\u1ecbch v\u1ee5 c\u00f3 th\u1ec3 kh\u00e1c.<\/p>\n\n<p class=\"wp-block-paragraph\">N\u1ebfu d\u1ecbch v\u1ee5 g\u1eb7p s\u1ef1 c\u1ed1, h\u00e3y ki\u1ec3m tra nh\u1eadt k\u00fd c\u1ee7a d\u1ecbch v\u1ee5:<\/p>\n\n<pre class=\"wp-block-code\"><code>sudo journalctl -u myapp -n 50<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">Ki\u1ec3m tra xem c\u00f3 s\u1ef1 c\u1ed1 ti\u1ebfn tr\u00ecnh, thi\u1ebfu th\u00e0nh ph\u1ea7n ph\u1ee5 thu\u1ed9c, l\u1ed7i c\u1ea5u h\u00ecnh ho\u1eb7c l\u1ed7i li\u00ean quan \u0111\u1ebfn b\u1ed9 nh\u1edb hay kh\u00f4ng.<\/p>\n\n<p class=\"wp-block-paragraph\">Ch\u1ec9 kh\u1edfi \u0111\u1ed9ng l\u1ea1i d\u1ecbch v\u1ee5 sau khi x\u00e1c \u0111\u1ecbnh v\u00e0 x\u1eed l\u00fd nguy\u00ean nh\u00e2n g\u1ed1c r\u1ec5.<\/p>\n\n<h2 id=\"h-3-verify-the-upstream-port-or-socket\" class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"3_Xac_minh_cong_hoac_socket_thuong_nguon\"><\/span>3. X\u00e1c minh c\u1ed5ng ho\u1eb7c socket th\u01b0\u1ee3ng ngu\u1ed3n<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n<p class=\"wp-block-paragraph\">Nginx ph\u1ea3i chuy\u1ec3n ti\u1ebfp y\u00eau c\u1ea7u \u0111\u1ebfn \u0111\u00fang \u0111\u1ecba ch\u1ec9 backend.<\/p>\n\n<p class=\"wp-block-paragraph\">V\u00ed d\u1ee5, c\u1ea5u h\u00ecnh proxy ng\u01b0\u1ee3c c\u00f3 th\u1ec3 ch\u1ee9a:<\/p>\n\n<pre class=\"wp-block-code\"><code>location \/ {\n    proxy_pass http:\/\/127.0.0.1:3000;\n}<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">C\u1ea5u h\u00ecnh n\u00e0y y\u00eau c\u1ea7u Nginx chuy\u1ec3n ti\u1ebfp y\u00eau c\u1ea7u \u0111\u1ebfn m\u1ed9t \u1ee9ng d\u1ee5ng HTTP \u0111ang l\u1eafng nghe tr\u00ean c\u1ed5ng 3000.<\/p>\n\n<p class=\"wp-block-paragraph\">Ki\u1ec3m tra xem c\u00f3 ti\u1ebfn tr\u00ecnh n\u00e0o \u0111ang l\u1eafng nghe tr\u00ean c\u1ed5ng \u0111\u00f3 kh\u00f4ng:<\/p>\n\n<pre class=\"wp-block-code\"><code>sudo ss -ltnp | grep ':3000'<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">B\u1ea1n c\u0169ng c\u00f3 th\u1ec3 ki\u1ec3m tra tr\u1ef1c ti\u1ebfp backend HTTP:<\/p>\n\n<pre class=\"wp-block-code\"><code>curl -i http:\/\/127.0.0.1:3000\/<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">N\u1ebfu backend kh\u00f4ng ho\u1ea1t \u0111\u1ed9ng, h\u00e3y ki\u1ec3m tra c\u1ea5u h\u00ecnh d\u1ecbch v\u1ee5 c\u1ee7a n\u00f3 tr\u01b0\u1edbc khi thay \u0111\u1ed5i Nginx.<\/p>\n\n<h3 id=\"h-check-php-fpm-sockets\" class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Kiem_tra_socket_PHP-FPM\"><\/span>Ki\u1ec3m tra socket PHP-FPM<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n<p class=\"wp-block-paragraph\">PHP-FPM th\u01b0\u1eddng s\u1eed d\u1ee5ng socket Unix ho\u1eb7c c\u1ed5ng TCP.<\/p>\n\n<p class=\"wp-block-paragraph\">C\u1ea5u h\u00ecnh Nginx c\u00f3 th\u1ec3 ch\u1ee9a:<\/p>\n\n<pre class=\"wp-block-code\"><code>fastcgi_pass unix:\/run\/php\/php8.3-fpm.sock;<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">Ki\u1ec3m tra xem socket \u0111\u00e3 c\u1ea5u h\u00ecnh c\u00f3 t\u1ed3n t\u1ea1i kh\u00f4ng:<\/p>\n\n<pre class=\"wp-block-code\"><code>ls -l \/run\/php\/<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">\u0110\u01b0\u1eddng d\u1eabn socket ph\u1ea3i kh\u1edbp v\u1edbi c\u00e0i \u0111\u1eb7t <code>listen<\/code> c\u1ee7a pool PHP-FPM, v\u00e0 Nginx ph\u1ea3i c\u00f3 quy\u1ec1n k\u1ebft n\u1ed1i.<\/p>\n\n<p class=\"wp-block-paragraph\"><strong>Quan tr\u1ecdng:<\/strong> <code>proxy_pass<\/code> \u0111\u01b0\u1ee3c d\u00f9ng cho c\u00e1c d\u1ecbch v\u1ee5 th\u01b0\u1ee3ng ngu\u1ed3n HTTP, c\u00f2n <code>fastcgi_pass<\/code> \u0111\u01b0\u1ee3c d\u00f9ng cho c\u00e1c d\u1ecbch v\u1ee5 <a href=\"https:\/\/en.wikipedia.org\/wiki\/FastCGI\">FastCGI<\/a> nh\u01b0 PHP-FPM. Kh\u00f4ng th\u1ec3 d\u00f9ng ch\u00fang thay th\u1ebf cho nhau.<\/p>\n\n<div class=\"wp-block-group zynoo-related-reading has-border-color has-text-color has-background is-layout-flow wp-block-group-is-layout-flow\" style=\"border-color:#c7d8ef;border-width:1px;border-radius:8px;border-left-color:#0069ff;border-left-width:3px;color:#24364f;background-color:#eaf2ff;margin-top:28px;margin-bottom:28px;padding-top:18px;padding-right:22px;padding-bottom:18px;padding-left:22px;font-size:16px;line-height:1.8\">\n<p class=\"wp-block-paragraph\"><strong>N\u1ebfu b\u1ea1n c\u1ea5u h\u00ecnh Nginx l\u1ea7n \u0111\u1ea7u, h\u00e3y \u0111\u1ea3m b\u1ea3o proxy_pass tr\u1ecf \u0111\u1ebfn \u0111\u00fang \u0111\u1ecba ch\u1ec9 backend.<\/strong> <a href=\"https:\/\/zynoo.com\/blog\/vi\/nginx-reverse-proxy-ubuntu\/\">H\u01b0\u1edbng d\u1eabn c\u1ea5u h\u00ecnh proxy ng\u01b0\u1ee3c Nginx tr\u00ean Ubuntu<\/a> c\u1ee7a ch\u00fang t\u00f4i tr\u00ecnh b\u00e0y c\u00e1ch thi\u1ebft l\u1eadp chuy\u1ec3n ti\u1ebfp y\u00eau c\u1ea7u, ki\u1ec3m tra c\u1ea5u h\u00ecnh v\u00e0 b\u1eadt HTTPS.<\/p>\n<\/div>\n\n<h2 id=\"h-4-check-server-memory-and-disk-space\" class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"4_Kiem_tra_bo_nho_va_dung_luong_o_dia_cua_may_chu\"><\/span>4. Ki\u1ec3m tra b\u1ed9 nh\u1edb v\u00e0 dung l\u01b0\u1ee3ng \u1ed5 \u0111\u0129a c\u1ee7a m\u00e1y ch\u1ee7<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n<p class=\"wp-block-paragraph\">C\u00e1c \u1ee9ng d\u1ee5ng backend c\u00f3 th\u1ec3 g\u1eb7p s\u1ef1 c\u1ed1 ho\u1eb7c ng\u1eebng ph\u1ea3n h\u1ed3i khi m\u00e1y ch\u1ee7 c\u1ea1n t\u00e0i nguy\u00ean.<\/p>\n\n<p class=\"wp-block-paragraph\">Ki\u1ec3m tra b\u1ed9 nh\u1edb:<\/p>\n\n<pre class=\"wp-block-code\"><code>free -h<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">Ki\u1ec3m tra dung l\u01b0\u1ee3ng \u1ed5 \u0111\u0129a:<\/p>\n\n<pre class=\"wp-block-code\"><code>df -h<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">Ki\u1ec3m tra c\u00e1c ti\u1ebfn tr\u00ecnh \u0111ang ch\u1ea1y:<\/p>\n\n<pre class=\"wp-block-code\"><code>top<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">N\u1ebfu m\u1ed9t \u1ee9ng d\u1ee5ng b\u1ecb ch\u1ea5m d\u1ee9t do thi\u1ebfu b\u1ed9 nh\u1edb, b\u1ea1n c\u00f3 th\u1ec3 t\u00ecm th\u1ea5y th\u00f4ng b\u00e1o li\u00ean quan trong nh\u1eadt k\u00fd h\u1ec7 th\u1ed1ng:<\/p>\n\n<pre class=\"wp-block-code\"><code>sudo journalctl -k --since \"1 hour ago\"<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">T\u00ecm c\u00e1c s\u1ef1 ki\u1ec7n h\u1ebft b\u1ed9 nh\u1edb ho\u1eb7c th\u00f4ng b\u00e1o ch\u1ea5m d\u1ee9t ti\u1ebfn tr\u00ecnh.<\/p>\n\n<p class=\"wp-block-paragraph\">N\u1ebfu \u1ed5 \u0111\u0129a \u0111\u00e3 h\u1ebft dung l\u01b0\u1ee3ng, h\u00e3y x\u00e1c \u0111\u1ecbnh d\u1eef li\u1ec7u n\u00e0o \u0111ang chi\u1ebfm dung l\u01b0\u1ee3ng tr\u01b0\u1edbc khi x\u00f3a t\u1ec7p.<\/p>\n\n<div class=\"wp-block-group zynoo-related-reading has-border-color has-text-color has-background is-layout-flow wp-block-group-is-layout-flow\" style=\"border-color:#c7d8ef;border-width:1px;border-radius:8px;border-left-color:#0069ff;border-left-width:3px;color:#24364f;background-color:#eaf2ff;margin-top:28px;margin-bottom:28px;padding-top:18px;padding-right:22px;padding-bottom:18px;padding-left:22px;font-size:16px;line-height:1.8\">\n<p class=\"wp-block-paragraph\"><strong>\u0110\u1ec3 bi\u1ebft th\u00eam c\u00e1c l\u1ec7nh gi\u00e1m s\u00e1t,<\/strong> h\u00e3y xem b\u00e0i vi\u1ebft <a href=\"https:\/\/zynoo.com\/blog\/vi\/linux-commands-for-server-management\/\">c\u00e1c l\u1ec7nh Linux thi\u1ebft y\u1ebfu \u0111\u1ec3 qu\u1ea3n l\u00fd m\u00e1y ch\u1ee7<\/a> c\u1ee7a ch\u00fang t\u00f4i.<\/p>\n<\/div>\n\n<h2 id=\"h-5-check-socket-permissions-and-application-logs\" class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"5_Kiem_tra_quyen_truy_cap_socket_va_nhat_ky_ung_dung\"><\/span>5. Ki\u1ec3m tra quy\u1ec1n truy c\u1eadp socket v\u00e0 nh\u1eadt k\u00fd \u1ee9ng d\u1ee5ng<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n<p class=\"wp-block-paragraph\">\u0110\u00f4i khi backend v\u1eabn \u0111ang ch\u1ea1y nh\u01b0ng Nginx kh\u00f4ng th\u1ec3 giao ti\u1ebfp v\u1edbi n\u00f3.<\/p>\n\n<p class=\"wp-block-paragraph\">\u0110\u1ed1i v\u1edbi socket Unix, h\u00e3y ki\u1ec3m tra ch\u1ee7 s\u1edf h\u1eefu v\u00e0 quy\u1ec1n truy c\u1eadp:<\/p>\n\n<pre class=\"wp-block-code\"><code>ls -l \/run\/php\/<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">N\u1ebfu nh\u1eadt k\u00fd b\u00e1o l\u1ed7i quy\u1ec1n truy c\u1eadp, h\u00e3y ki\u1ec3m tra c\u1ea3 c\u00e1c th\u01b0 m\u1ee5c tr\u00ean \u0111\u01b0\u1eddng d\u1eabn \u0111\u1ebfn socket.<\/p>\n\n<p class=\"wp-block-paragraph\">Quy\u1ec1n truy c\u1eadp ph\u00f9 h\u1ee3p ph\u1ee5 thu\u1ed9c v\u00e0o ng\u01b0\u1eddi d\u00f9ng ch\u1ea1y c\u00e1c ti\u1ebfn tr\u00ecnh worker c\u1ee7a Nginx v\u00e0 c\u1ea5u h\u00ecnh d\u1ecbch v\u1ee5 backend.<\/p>\n\n<p class=\"wp-block-paragraph\">Tr\u00e1nh c\u1ea5p quy\u1ec1n qu\u00e1 r\u1ed9ng, ch\u1eb3ng h\u1ea1n nh\u01b0 <code>chmod 777<\/code>. Thay v\u00e0o \u0111\u00f3, h\u00e3y \u0111i\u1ec1u ch\u1ec9nh c\u1ea5u h\u00ecnh d\u1ecbch v\u1ee5 ho\u1eb7c pool li\u00ean quan \u0111\u1ec3 c\u00e1c ti\u1ebfn tr\u00ecnh \u0111\u01b0\u1ee3c ph\u00e9p c\u00f3 th\u1ec3 truy c\u1eadp socket.<\/p>\n\n<p class=\"wp-block-paragraph\">N\u1ebfu nh\u1eadt k\u00fd l\u1ed7i cho th\u1ea5y d\u1ecbch v\u1ee5 th\u01b0\u1ee3ng ngu\u1ed3n \u0111\u00f3ng k\u1ebft n\u1ed1i qu\u00e1 s\u1edbm, h\u00e3y ki\u1ec3m tra nh\u1eadt k\u00fd \u1ee9ng d\u1ee5ng backend \u0111\u1ec3 t\u00ecm c\u00e1c s\u1ef1 c\u1ed1, ngo\u1ea1i l\u1ec7 ho\u1eb7c y\u00eau c\u1ea7u th\u1ea5t b\u1ea1i.<\/p>\n\n<h2 id=\"h-6-test-your-nginx-configuration\" class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"6_Kiem_tra_cau_hinh_Nginx\"><\/span>6. Ki\u1ec3m tra c\u1ea5u h\u00ecnh Nginx<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n<p class=\"wp-block-paragraph\">C\u00e0i \u0111\u1eb7t proxy kh\u00f4ng ch\u00ednh x\u00e1c ho\u1eb7c c\u00e1c thay \u0111\u1ed5i c\u1ea5u h\u00ecnh c\u0169ng c\u00f3 th\u1ec3 l\u00e0m gi\u00e1n \u0111o\u1ea1n giao ti\u1ebfp v\u1edbi d\u1ecbch v\u1ee5 th\u01b0\u1ee3ng ngu\u1ed3n.<\/p>\n\n<p class=\"wp-block-paragraph\">Tr\u01b0\u1edbc khi \u00e1p d\u1ee5ng thay \u0111\u1ed5i, h\u00e3y x\u00e1c th\u1ef1c c\u1ea5u h\u00ecnh Nginx:<\/p>\n\n<pre class=\"wp-block-code\"><code>sudo nginx -t<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">N\u1ebfu ki\u1ec3m tra th\u00e0nh c\u00f4ng, h\u00e3y t\u1ea3i l\u1ea1i c\u1ea5u h\u00ecnh Nginx:<\/p>\n\n<pre class=\"wp-block-code\"><code>sudo systemctl reload nginx<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">Vi\u1ec7c t\u1ea3i l\u1ea1i s\u1ebd \u00e1p d\u1ee5ng c\u00e1c thay \u0111\u1ed5i c\u1ea5u h\u00ecnh h\u1ee3p l\u1ec7 m\u00e0 kh\u00f4ng c\u1ea7n kh\u1edfi \u0111\u1ed9ng l\u1ea1i d\u1ecbch v\u1ee5.<\/p>\n\n<p class=\"wp-block-paragraph\">N\u1ebfu ki\u1ec3m tra kh\u00f4ng th\u00e0nh c\u00f4ng, tr\u01b0\u1edbc ti\u00ean h\u00e3y s\u1eeda l\u1ed7i c\u1ea5u h\u00ecnh \u0111\u01b0\u1ee3c b\u00e1o.<\/p>\n\n<p class=\"wp-block-paragraph\">\u0110\u1eebng t\u00f9y ti\u1ec7n t\u0103ng th\u1eddi gian ch\u1edd proxy ho\u1eb7c gi\u1edbi h\u1ea1n b\u1ed9 \u0111\u1ec7m. Nh\u1eefng \u0111i\u1ec1u ch\u1ec9nh n\u00e0y s\u1ebd kh\u00f4ng kh\u1eafc ph\u1ee5c \u0111\u01b0\u1ee3c t\u00ecnh tr\u1ea1ng backend \u0111\u00e3 d\u1eebng, socket kh\u00f4ng ch\u00ednh x\u00e1c ho\u1eb7c k\u1ebft n\u1ed1i b\u1ecb t\u1eeb ch\u1ed1i.<\/p>\n\n<h2 id=\"h-7-confirm-that-the-502-error-is-fixed\" class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"7_Xac_nhan_loi_502_da_duoc_khac_phuc\"><\/span>7. X\u00e1c nh\u1eadn l\u1ed7i 502 \u0111\u00e3 \u0111\u01b0\u1ee3c kh\u1eafc ph\u1ee5c<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n<p class=\"wp-block-paragraph\">Sau khi x\u1eed l\u00fd nguy\u00ean nh\u00e2n g\u1ed1c r\u1ec5, h\u00e3y ki\u1ec3m tra URL b\u1ecb \u1ea3nh h\u01b0\u1edfng:<\/p>\n\n<pre class=\"wp-block-code\"><code>curl -I https:\/\/example.com<\/code><\/pre>\n\n<p class=\"wp-block-paragraph\">Thay <code>example.com<\/code> b\u1eb1ng t\u00ean mi\u1ec1n th\u1ef1c t\u1ebf c\u1ee7a b\u1ea1n.<\/p>\n\n<p class=\"wp-block-paragraph\">M\u1ed9t y\u00eau c\u1ea7u th\u00e0nh c\u00f4ng th\u01b0\u1eddng tr\u1ea3 v\u1ec1 m\u00e3 tr\u1ea1ng th\u00e1i HTTP ph\u00f9 h\u1ee3p nh\u01b0 <code>200 OK<\/code>, m\u1eb7c d\u00f9 chuy\u1ec3n h\u01b0\u1edbng v\u00e0 c\u00e1c ph\u1ea3n h\u1ed3i h\u1ee3p l\u1ec7 kh\u00e1c c\u00f3 th\u1ec3 tr\u1ea3 v\u1ec1 m\u00e3 kh\u00e1c.<\/p>\n\n<p class=\"wp-block-paragraph\">\u0110\u1ed3ng th\u1eddi, h\u00e3y m\u1edf trang web trong tr\u00ecnh duy\u1ec7t v\u00e0 ki\u1ec3m tra l\u1ea1i nh\u1eadt k\u00fd l\u1ed7i c\u1ee7a Nginx.<\/p>\n\n<p class=\"wp-block-paragraph\">N\u1ebfu l\u1ed7i xu\u1ea5t hi\u1ec7n tr\u1edf l\u1ea1i khi m\u00e1y ch\u1ee7 ch\u1ecbu t\u1ea3i, h\u00e3y gi\u00e1m s\u00e1t d\u1ecbch v\u1ee5 backend v\u00e0 m\u1ee9c s\u1eed d\u1ee5ng t\u00e0i nguy\u00ean trong l\u00fac t\u00e1i hi\u1ec7n s\u1ef1 c\u1ed1.<\/p>\n\n<h2 id=\"h-how-to-prevent-nginx-502-errors\" class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Cach_ngan_ngua_loi_502_trong_Nginx\"><\/span>C\u00e1ch ng\u0103n ng\u1eeba l\u1ed7i 502 trong Nginx<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n<p class=\"wp-block-paragraph\">Kh\u00f4ng ph\u1ea3i m\u1ecdi s\u1ef1 c\u1ed1 backend \u0111\u1ec1u c\u00f3 th\u1ec3 ng\u0103n ng\u1eeba, nh\u01b0ng qu\u1ea3n tr\u1ecb m\u00e1y ch\u1ee7 t\u1ed1t s\u1ebd gi\u00fap gi\u1ea3m c\u00e1c l\u1ea7n gi\u00e1n \u0111o\u1ea1n d\u1ecbch v\u1ee5 c\u00f3 th\u1ec3 tr\u00e1nh \u0111\u01b0\u1ee3c.<\/p>\n\n<ul class=\"wp-block-list\">\n<li>Gi\u00e1m s\u00e1t t\u00ecnh tr\u1ea1ng ho\u1ea1t \u0111\u1ed9ng c\u1ee7a Nginx v\u00e0 d\u1ecbch v\u1ee5 backend.<\/li>\n\n\n\n<li>Ki\u1ec3m tra nh\u1eadt k\u00fd \u1ee9ng d\u1ee5ng sau m\u1ed7i l\u1ea7n tri\u1ec3n khai.<\/li>\n\n\n\n<li>C\u1ea5u h\u00ecnh ch\u00ednh s\u00e1ch kh\u00f4i ph\u1ee5c d\u1ecbch v\u1ee5 ph\u00f9 h\u1ee3p.<\/li>\n\n\n\n<li>Gi\u00e1m s\u00e1t m\u1ee9c s\u1eed d\u1ee5ng b\u1ed9 nh\u1edb, dung l\u01b0\u1ee3ng l\u01b0u tr\u1eef v\u00e0 s\u1ed1 l\u01b0\u1ee3ng k\u1ebft n\u1ed1i.<\/li>\n\n\n\n<li>X\u00e1c th\u1ef1c c\u00e1c thay \u0111\u1ed5i c\u1ea5u h\u00ecnh tr\u01b0\u1edbc khi \u00e1p d\u1ee5ng.<\/li>\n\n\n\n<li>Ki\u1ec3m tra tr\u1ef1c ti\u1ebfp \u1ee9ng d\u1ee5ng tr\u01b0\u1edbc khi \u0111\u1ecbnh tuy\u1ebfn l\u01b0u l\u01b0\u1ee3ng truy c\u1eadp qua Nginx.<\/li>\n<\/ul>\n\n<p class=\"wp-block-paragraph\">N\u1ebfu \u1ee9ng d\u1ee5ng c\u1ea7n th\u00eam t\u00e0i nguy\u00ean, h\u00e3y \u0111o m\u1ee9c s\u1eed d\u1ee5ng th\u1ef1c t\u1ebf tr\u01b0\u1edbc khi quy\u1ebft \u0111\u1ecbnh n\u00e2ng c\u1ea5p n\u0103ng l\u1ef1c m\u00e1y ch\u1ee7.<\/p>\n\n<div class=\"wp-block-group zynoo-related-reading has-border-color has-text-color has-background is-layout-flow wp-block-group-is-layout-flow\" style=\"border-color:#c7d8ef;border-width:1px;border-radius:8px;border-left-color:#0069ff;border-left-width:3px;color:#24364f;background-color:#eaf2ff;margin-top:28px;margin-bottom:28px;padding-top:18px;padding-right:22px;padding-bottom:18px;padding-left:22px;font-size:16px;line-height:1.8\">\n<p class=\"wp-block-paragraph\">L\u1ed7i 502 cho bi\u1ebft m\u00e1y ch\u1ee7 th\u01b0\u1ee3ng ngu\u1ed3n tr\u1ea3 v\u1ec1 ph\u1ea3n h\u1ed3i kh\u00f4ng h\u1ee3p l\u1ec7, c\u00f2n <strong>l\u1ed7i 504<\/strong> x\u1ea3y ra khi m\u00e1y ch\u1ee7 th\u01b0\u1ee3ng ngu\u1ed3n m\u1ea5t qu\u00e1 nhi\u1ec1u th\u1eddi gian \u0111\u1ec3 ph\u1ea3n h\u1ed3i. N\u1ebfu b\u1ea1n g\u1eb7p l\u1ed7i 504, h\u00e3y l\u00e0m theo h\u01b0\u1edbng d\u1eabn kh\u1eafc ph\u1ee5c <a href=\"https:\/\/zynoo.com\/blog\/vi\/504-gateway-timeout\/\">l\u1ed7i 504 Gateway Timeout<\/a> c\u1ee7a ch\u00fang t\u00f4i \u0111\u1ec3 ch\u1ea9n \u0111o\u00e1n v\u00e0 x\u1eed l\u00fd \u1ee9ng d\u1ee5ng ph\u1ea3n h\u1ed3i ch\u1eadm, v\u1ea5n \u0111\u1ec1 v\u1ec1 t\u00e0i nguy\u00ean m\u00e1y ch\u1ee7 v\u00e0 c\u00e0i \u0111\u1eb7t th\u1eddi gian ch\u1edd proxy.<\/p>\n<\/div>\n\n<h2 id=\"h-frequently-asked-questions\" class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Cau_hoi_thuong_gap\"><\/span>C\u00e2u h\u1ecfi th\u01b0\u1eddng g\u1eb7p<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n<div class=\"schema-faq wp-block-yoast-faq-block\"><div class=\"schema-faq-section\" id=\"faq-question-1793529208055\"><strong class=\"schema-faq-question\">L\u1ed7i 502 Bad Gateway trong Nginx c\u00f3 ngh\u0129a l\u00e0 g\u00ec?<\/strong> <p class=\"schema-faq-answer\">\u0110i\u1ec1u \u0111\u00f3 c\u00f3 ngh\u0129a l\u00e0 Nginx, khi \u0111\u00f3ng vai tr\u00f2 c\u1ed5ng k\u1ebft n\u1ed1i ho\u1eb7c proxy, \u0111\u00e3 nh\u1eadn \u0111\u01b0\u1ee3c ph\u1ea3n h\u1ed3i kh\u00f4ng h\u1ee3p l\u1ec7 t\u1eeb m\u00e1y ch\u1ee7 th\u01b0\u1ee3ng ngu\u1ed3n. Nguy\u00ean nh\u00e2n th\u01b0\u1eddng l\u00e0 d\u1ecbch v\u1ee5 backend \u0111\u00e3 d\u1eebng ho\u1eb7c c\u00f3 v\u1ea5n \u0111\u1ec1 v\u1edbi k\u1ebft n\u1ed1i th\u01b0\u1ee3ng ngu\u1ed3n.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1793529240063\"><strong class=\"schema-faq-question\">Kh\u1edfi \u0111\u1ed9ng l\u1ea1i Nginx c\u00f3 kh\u1eafc ph\u1ee5c \u0111\u01b0\u1ee3c l\u1ed7i 502 kh\u00f4ng?<\/strong> <p class=\"schema-faq-answer\">Kh\u00f4ng h\u1eb3n. Kh\u1edfi \u0111\u1ed9ng l\u1ea1i ho\u1eb7c t\u1ea3i l\u1ea1i c\u1ea5u h\u00ecnh Nginx s\u1ebd kh\u00f4ng kh\u1eafc ph\u1ee5c \u0111\u01b0\u1ee3c \u1ee9ng d\u1ee5ng kh\u00f4ng ho\u1ea1t \u0111\u1ed9ng, c\u1ed5ng backend kh\u00f4ng ch\u00ednh x\u00e1c ho\u1eb7c socket PHP-FPM b\u1ecb thi\u1ebfu.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1793529252450\"><strong class=\"schema-faq-question\">HTTP 502 v\u00e0 HTTP 504 kh\u00e1c nhau th\u1ebf n\u00e0o?<\/strong> <p class=\"schema-faq-answer\">L\u1ed7i 502 cho bi\u1ebft m\u00e1y ch\u1ee7 th\u01b0\u1ee3ng ngu\u1ed3n tr\u1ea3 v\u1ec1 ph\u1ea3n h\u1ed3i kh\u00f4ng h\u1ee3p l\u1ec7, c\u00f2n l\u1ed7i 504 c\u00f3 ngh\u0129a l\u00e0 c\u1ed5ng k\u1ebft n\u1ed1i kh\u00f4ng nh\u1eadn \u0111\u01b0\u1ee3c ph\u1ea3n h\u1ed3i t\u1eeb m\u00e1y ch\u1ee7 th\u01b0\u1ee3ng ngu\u1ed3n trong th\u1eddi gian ch\u1edd.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1793529289265\"><strong class=\"schema-faq-question\">RAM th\u1ea5p c\u00f3 th\u1ec3 g\u00e2y ra l\u1ed7i 502 Bad Gateway kh\u00f4ng?<\/strong> <p class=\"schema-faq-answer\">C\u00f3. Vi\u1ec7c c\u1ea1n b\u1ed9 nh\u1edb c\u00f3 th\u1ec3 khi\u1ebfn c\u00e1c ti\u1ebfn tr\u00ecnh backend g\u1eb7p s\u1ef1 c\u1ed1 ho\u1eb7c b\u1ecb ch\u1ea5m d\u1ee9t, khi\u1ebfn Nginx kh\u00f4ng th\u1ec3 giao ti\u1ebfp v\u1edbi ch\u00fang.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1793529308749\"><strong class=\"schema-faq-question\">L\u1ed7i 502 c\u00f3 ph\u1ea3i l\u00fac n\u00e0o c\u0169ng do Nginx g\u00e2y ra kh\u00f4ng?<\/strong> <p class=\"schema-faq-answer\">Kh\u00f4ng. C\u00e1c c\u1ed5ng k\u1ebft n\u1ed1i, proxy, CDN v\u00e0 b\u1ed9 c\u00e2n b\u1eb1ng t\u1ea3i kh\u00e1c c\u0169ng c\u00f3 th\u1ec3 tr\u1ea3 v\u1ec1 l\u1ed7i HTTP 502.<\/p> <\/div> <\/div>\n\n<h2 id=\"h-conclusion\" class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Ket_luan\"><\/span>K\u1ebft lu\u1eadn<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n<p class=\"wp-block-paragraph\">\u0110\u1ec3 kh\u1eafc ph\u1ee5c <strong>l\u1ed7i 502 Bad Gateway trong Nginx<\/strong>, tr\u01b0\u1edbc ti\u00ean b\u1ea1n c\u1ea7n x\u00e1c \u0111\u1ecbnh v\u00ec sao \u1ee9ng d\u1ee5ng th\u01b0\u1ee3ng ngu\u1ed3n kh\u00f4ng ph\u1ea3n h\u1ed3i \u0111\u00fang c\u00e1ch.<\/p>\n\n<p class=\"wp-block-paragraph\">Tr\u01b0\u1edbc ti\u00ean, h\u00e3y ki\u1ec3m tra nh\u1eadt k\u00fd l\u1ed7i c\u1ee7a Nginx, x\u00e1c nh\u1eadn d\u1ecbch v\u1ee5 backend \u0111ang ch\u1ea1y v\u00e0 x\u00e1c minh c\u1ed5ng ho\u1eb7c socket \u0111\u00e3 c\u1ea5u h\u00ecnh. Sau \u0111\u00f3, h\u00e3y ki\u1ec3m tra gi\u1edbi h\u1ea1n t\u00e0i nguy\u00ean, quy\u1ec1n truy c\u1eadp v\u00e0 c\u00e1c s\u1ef1 c\u1ed1 \u1ee9ng d\u1ee5ng.<\/p>\n\n<p class=\"wp-block-paragraph\">Trong h\u1ea7u h\u1ebft tr\u01b0\u1eddng h\u1ee3p, x\u00e1c \u0111\u1ecbnh ch\u00ednh x\u00e1c s\u1ef1 c\u1ed1 th\u01b0\u1ee3ng ngu\u1ed3n s\u1ebd hi\u1ec7u qu\u1ea3 h\u01a1n vi\u1ec7c li\u00ean t\u1ee5c kh\u1edfi \u0111\u1ed9ng l\u1ea1i Nginx ho\u1eb7c thay \u0111\u1ed5i c\u00e0i \u0111\u1eb7t th\u1eddi gian ch\u1edd.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>L\u1ed7i 502 Bad Gateway trong Nginx th\u01b0\u1eddng c\u00f3 ngh\u0129a l\u00e0 Nginx kh\u00f4ng nh\u1eadn \u0111\u01b0\u1ee3c ph\u1ea3n h\u1ed3i h\u1ee3p l\u1ec7 t\u1eeb m\u00e1y ch\u1ee7 th\u01b0\u1ee3ng ngu\u1ed3n, ch\u1eb3ng h\u1ea1n nh\u01b0 PHP-FPM, Node.js ho\u1eb7c m\u1ed9t \u1ee9ng d\u1ee5ng backend kh\u00e1c. Nh\u1eefng nguy\u00ean nh\u00e2n ph\u1ed5 bi\u1ebfn nh\u1ea5t l\u00e0 d\u1ecbch v\u1ee5 \u1ee9ng d\u1ee5ng \u0111\u00e3 d\u1eebng, c\u1ed5ng ho\u1eb7c socket th\u01b0\u1ee3ng ngu\u1ed3n \u0111\u01b0\u1ee3c c\u1ea5u h\u00ecnh [&hellip;]<\/p>\n","protected":false},"author":8,"featured_media":5060,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[654],"tags":[],"class_list":["post-5059","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-huong-dan-linux"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v27.4 (Yoast SEO v28.8) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>C\u00e1ch kh\u1eafc ph\u1ee5c l\u1ed7i 502 Bad Gateway trong Nginx (t\u1eebng b\u01b0\u1edbc)<\/title>\n<meta name=\"description\" content=\"Kh\u1eafc ph\u1ee5c l\u1ed7i 502 Bad Gateway trong Nginx b\u1eb1ng c\u00e1ch ki\u1ec3m tra nh\u1eadt k\u00fd, m\u00e1y ch\u1ee7 th\u01b0\u1ee3ng ngu\u1ed3n, PHP-FPM, c\u00e0i \u0111\u1eb7t proxy v\u00e0 t\u00e0i nguy\u00ean m\u00e1y ch\u1ee7 b\u1eb1ng c\u00e1c l\u1ec7nh Linux.\" \/>\n<meta name=\"robots\" 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