Bài Toán: Một ngày đẹp trời, 1 ý tưởng thật dị hợm nảy ra trong đầu:

• Liệu nginx có thể đứng trước làm proxy reverse cho KubeAPI không?
• Liệu cùng chung IP:port, nhưng khác domain thì có thể kết nối các cụm cluster khác nhau được không?

Thực hiện:

Phần 1: Nginx Proxy_Pass tới kube-api

Kiến trúc: Admin ---> Nginx ---> KubeAPI

Bước 1.1 Cài OpenResty (Hoặc Nginx)

Các bạn có thể cài nginx hoặc openresty đều được. Mục đích mình cài Openrestry (khi cài openresty sẽ có luôn nginx) là để sử dụng cho phần 2.

# Dành cho CenOS ( https://openresty.org/en/linux-packages.html )
cd /etc/yum.repo.d/
curl -O https://openresty.org/package/centos/openresty.repo
yum install openresty
systemctl start openresty
systemctl enable openresty # Dành cho Ubuntu
Làm theo hướng dẫn link này: https://blog.openresty.com/en/ubuntu20-or-install/
apt-get update
apt-get -y install --no-install-recommends openresty
systemctl start openresty
systemctl enable openresty

Bước 1.2 : Cấu hình nginx.conf

vim /usr/local/openresty/nginx/conf/nginx.conf Thêm cầu hình proxy mới như sau:

server { listen 6444 ssl; server_name kubeapi.xxx.com; ssl_certificate /etc/kubernetes/pki/apiserver.crt; ssl_certificate_key /etc/kubernetes/pki/apiserver.key; location / { proxy_pass https://127.0.0.1:6443; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Host kubeapi.xxx.com; proxy_ssl_certificate /etc/kubernetes/pki/apiserver-kubelet-client.crt; proxy_ssl_certificate_key /etc/kubernetes/pki/apiserver-kubelet-client.key; }
} Reload lại OpenResty Nginx
systemctl reload openresty

Sửa kube config trỏ vào pod mới 6443 -> 6444

sed -i -e 's/6443/6444/g' ~/.kube/config

Test kiểm tra get api và logs nginx

# kubectl get node -v=6
I1117 13:26:50.223517 36661 round_trippers.go:553] GET https://192.168.88.12:6444/api?timeout=32s 200 OK in 25 milliseconds
I1117 13:26:50.231582 36661 round_trippers.go:553] GET https://192.168.88.12:6444/apis?timeout=32s 200 OK in 5 milliseconds
I1117 13:26:50.262655 36661 round_trippers.go:553] GET https://192.168.88.12:6444/api/v1/nodes?limit=500 200 OK in 5 milliseconds
NAME STATUS ROLES AGE VERSION
master-node Ready control-plane 4d20h v1.30.0
worker-node1 Ready <none> 4d20h v1.29.8

# tail /usr/local/openresty/nginx/logs/access.log -n 1
192.168.88.12 - - [17/Nov/2024:13:26:50 +0000] "GET /api/v1/nodes?limit=500 HTTP/1.1" 200 9242 "-" "kubectl/v1.30.0 (linux/amd64) kubernetes/7c48c2b"

*** Ý tưởng nữa hiện ra trong đầu, liệu bung luôn cả request và response của nó ra logs được không...next phần 2

Phần 2: Nginx đóng vai trò AuditLogs

Cầu hình thêm nginx.conf bổ xung log_format, access_log và lua

vim /usr/local/openresty/nginx/conf/nginx.conf

http { include mime.types; default_type application/octet-stream; sendfile on; keepalive_timeout 65; log_format log_req_resp escape=none '$remote_addr - $remote_user [$time_local] ' ' "$request" $status $body_bytes_sent ${request_time}ms ' '| PRINT_REQUEST_BODY: $request_body ' '| PRINT_REQUEST_HEADER:"$req_header" ' '| PRINT_RESPONSE_HEADER:"$resp_header" ' '| PRINT_RESPONSE_BODY:"$resp_body" '; access_log logs/access.log log_req_resp; #Default 80 server { listen 80; server_name localhost; location / { root html; index index.html index.htm; } error_page 500 502 503 504 /50x.html; location = /50x.html { root html; } } # Cấu hình 6444 log request và response server { listen 6444 ssl; server_name kubeapi.xxx.com; ssl_certificate /etc/kubernetes/pki/apiserver.crt; ssl_certificate_key /etc/kubernetes/pki/apiserver.key; location / { #Step2: Config REPSONSE_BODY lua_need_request_body on; set $resp_body ""; body_filter_by_lua ' local resp_body = string.sub(ngx.arg[1], 1, 1000000) ngx.ctx.buffered = (ngx.ctx.buffered or "") .. resp_body if ngx.arg[2] then ngx.var.resp_body = ngx.ctx.buffered end '; #Step3: Config REQUEST_HEADER, RESPONSE_HEADER set $req_header ""; set $resp_header ""; header_filter_by_lua ' local h = ngx.req.get_headers() for k, v in pairs(h) do ngx.var.req_header = ngx.var.req_header .. k.."="..v.." " end local rh = ngx.resp.get_headers() for k, v in pairs(rh) do ngx.var.resp_header = ngx.var.resp_header .. k.."="..v.." " end '; proxy_pass https://127.0.0.1:6443; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Host kubeapi.xxx.com; proxy_ssl_certificate /etc/kubernetes/pki/apiserver-kubelet-client.crt; proxy_ssl_certificate_key /etc/kubernetes/pki/apiserver-kubelet-client.key; }
} } 

Kết quả

# kubectl get node -v=6
I1117 13:37:22.883328 39935 round_trippers.go:553] GET https://192.168.88.12:6444/api/v1/nodes?limit=500 200 OK in 13 milliseconds
NAME STATUS ROLES AGE VERSION
master-node Ready control-plane 4d20h v1.30.0
worker-node1 Ready <none> 4d20h v1.29.8 tail -n1 /var/log/nginx/access.log
192.168.88.12 - [17/Nov/2024:13:34:58 +0000] "GET /api/v1/nodes?limit=500 HTTP/1.1" 200 9242 0.010ms | PRINT_REQUEST_BODY: | PRINT_REQUEST_HEADER:"host=192.168.88.12:6444 user-agent=kubectl/v1.30.0 (linux/amd64) kubernetes/7c48c2b accept=application/json;as=Table;v=v1;g=meta.k8s.io,application/json;as=Table;v=v1beta1;g=meta.k8s.io,application/json accept-encoding=gzip kubectl-command=kubectl get kubectl-session=8b063f81-279c-47dc-a39b-fc42abff2dcb " | PRINT_RESPONSE_HEADER:"cache-control=no-cache, private content-type=application/json connection=keep-alive x-kubernetes-pf-prioritylevel-uid=c7bb2e92-7125-47ee-b8af-b0da52a06199 audit-id=d4859fdd-7e70-4791-81ea-5d5a02d02d1d x-kubernetes-pf-flowschema-uid=c2ed420f-f18f-4d80-aaf1-291dd5dc931d " | PRINT_RESPONSE_BODY:"{"kind":"Table","apiVersion":"meta.k8s.io/v1","metadata":{"resourceVersion":"120353"},"columnDefinitions":[{"name":"Name","type":"string","format":"name","description":"Name must be unique within a namespace. Is required when creating resources, although some resources may allow a client to request the generation of an appropriate name automatically. Name is primarily intended for creation idempotence and configuration definition. Cannot be updated. More info: https://kubernetes.io/docs/concepts/overview/working-with-objects/names#names","priority":0},{"name":"Status","type":"string","format":"","description":"The status of the node","priority":0},{"name":"Roles","type":"string","format":"","description":"The roles of the node","priority":0},{"name":"Age","type":"string","format":"","description":"CreationTimestamp is a timestamp representing the server time when this object was created. It is not guaranteed to be set in happens-before order across separate operations. Clients may not set this value. It is represented in RFC3339 form and is in UTC.\n\nPopulated by the system. Read-only. Null for lists. More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata","priority":0},{"name":"Version","type":"string","format":"","description":"Kubelet Version reported by the node.","priority":0},{"name":"Internal-IP","type":"string","format":"","description":"List of addresses reachable to the node. Queried from cloud provider, if available. More info: https://kubernetes.io/docs/concepts/nodes/node/#addresses Note: This field is declared as mergeable, but the merge key is not sufficiently unique, which can cause data corruption when it is merged. Callers should instead use a full-replacement patch. See https://pr.k8s.io/79391 for an example. Consumers should assume that addresses can change during the lifetime of a Node. However, there are some exceptions where this may not be possible, such as Pods that inherit a Node's address in its own status or consumers of the downward API (status.hostIP).","priority":1},{"name":"External-IP","type":"string","format":"","description":"List of addresses reachable to the node. Queried from cloud provider, if available. More info: https://kubernetes.io/docs/concepts/nodes/node/#addresses Note: This field is declared as mergeable, but the merge key is not sufficiently unique, which can cause data corruption when it is merged. Callers should instead use a full-replacement patch. See https://pr.k8s.io/79391 for an example. Consumers should assume that addresses can change during the lifetime of a Node. However, there are some exceptions where this may not be possible, such as Pods that inherit a Node's address in its own status or consumers of the downward API (status.hostIP).","priority":1},{"name":"OS-Image","type":"string","format":"","description":"OS Image reported by the node from /etc/os-release (e.g. Debian GNU/Linux 7 (wheezy)).","priority":1},{"name":"Kernel-Version","type":"string","format":"","description":"Kernel Version reported by the node from 'uname -r' (e.g. 3.16.0-0.bpo.4-amd64).","priority":1},{"name":"Container-Runtime","type":"string","format":"","description":"ContainerRuntime Version reported by the node through runtime remote API (e.g. containerd://1.4.2).","priority":1}],"rows":[{"cells":["master-node","Ready","control-plane","4d20h","v1.30.0","192.168.88.12","\u003cnone\u003e","Ubuntu 22.04.5 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22.04.5 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

Kết quả không đẹp đẽ như bật Kube AuditLogs trực tiếp từ Policy vì nội dung trả về khá nhiều, như vậy sẽ làm đầy ổ cứng rất nhanh. Nhưng cũng là 1 phương án thay thế có thể áp dụng.. ta có thể dùng logrotate để nén log và lưu trữ trong 1 khoảng thời gian nhất định.

(*Bài viết chỉ mang tính chất ý tưởng và chưa áp dụng vào thực tế... ^^)

(Nguồn tham khảo https://gist.github.com/gilangvperdana/2c4877c8efb729534e7f7c55e6e1e2d3 )