### HTTP/3 and QUIC Configuration Example

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http_v3

Example configuration for enabling HTTP/3 and QUIC on a server, including SSL/TLS setup and logging.

```APIDOC
## HTTP/3 and QUIC Configuration Example

### Description
This example demonstrates how to configure Nginx to support HTTP/3 and QUIC. It includes setting up SSL certificates, listening on specific ports for both HTTP/2 and QUIC, and defining a custom log format.

### Method
N/A (Configuration file)

### Endpoint
N/A (Configuration file)

### Parameters
N/A

### Request Example
```nginx
http {
    log_format quic '$remote_addr - $remote_user [$time_local] ';
                    '"$request" $status $body_bytes_sent ';
                    '"$http_referer" "$http_user_agent" "$http3"';

    access_log logs/access.log quic;

    server {
        listen 8443 quic reuseport;
        listen 8443 ssl;

        ssl_certificate     certs/example.com.crt;
        ssl_certificate_key certs/example.com.key;

        location / {
            add_header Alt-Svc 'h3=":8443"; ma=86400';
        }
    }
}
```

### Response
N/A (Configuration applies to server behavior)

### Notes
- For better compatibility, it is recommended to use the same port for HTTP/3 and HTTPS.
- To accept HTTP/3 connections over TLS, TLSv1.3 support (OpenSSL 1.1.1+) is required.
- The `reuseport` option can only be specified in one `listen ... quic` directive per server. Other `listen ... quic` directives should not include it.
```

--------------------------------

### Cloud-Init Meta-Data Example

Source: https://angie.software/adc/docs/install/cloud-init/install-qcow2-0.5

Example configuration for the meta-data file used in cloud-init ISO images. It specifies the instance ID and local hostname for the virtual machine.

```yaml
instance-id: my-adc1       # уникальный идентификатор виртуальной машины
local-hostname: my-server  # имя хоста виртуальной машины


```

--------------------------------

### Install QEMU on Ubuntu/Debian

Source: https://angie.software/adc/docs/install/install-qcow2

Installs QEMU and necessary KVM/libvirt components on Ubuntu and Debian systems using the APT package manager. This setup is required for virtual machine management and deployment.

```bash
sudo apt update
sudo apt install -y \
  qemu-kvm qemu-system-x86 qemu-utils \
  libvirt-daemon-system libvirt-clients virtinst virt-manager \
  ovmf cpu-checker

```

--------------------------------

### Install QEMU on Fedora

Source: https://angie.software/adc/docs/install/cloud-init/install-qcow2-0.5

Installs necessary QEMU and libvirt packages on Fedora systems using the DNF package manager. This includes utilities for virtualization management.

```bash
$ sudo dnf install qemu libvirt libguestfs-tools libguestfs virt-viewer virt-install

```

--------------------------------

### Install QEMU on Ubuntu/Debian

Source: https://angie.software/adc/docs/install/cloud-init/install-qcow2-0.5

Installs QEMU, libvirt, and related tools on Ubuntu and Debian systems using the APT package manager. Ensures all required components for KVM virtualization are present.

```bash
$ sudo apt update
$ sudo apt install -y \
  qemu-kvm qemu-system-x86 qemu-utils \
  libvirt-daemon-system libvirt-clients virtinst virt-manager \
  ovmf cpu-checker

```

--------------------------------

### MP4 Pseudo-Streaming URL Example

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http_mp4

Demonstrates a typical URL format for requesting an MP4 file with pseudo-streaming enabled, specifying a start time. This allows players to initiate playback from a specific point in the file.

```http
http://example.com/elephants_dream.mp4?start=238.88
```

--------------------------------

### Install QEMU on Fedora

Source: https://angie.software/adc/docs/install/install-qcow2

Installs QEMU and related virtualization utilities on Fedora systems using the DNF package manager. This is a prerequisite for deploying virtual machine images like qcow2.

```bash
sudo dnf install qemu libvirt libguestfs-tools libguestfs virt-viewer virt-install

```

--------------------------------

### Listen Directive Syntax and Examples (Angie)

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http

This snippet details the various syntaxes for the 'listen' directive in Angie, including IP addresses, hostnames, ports, and UNIX domain sockets. It also provides examples of how to specify addresses and ports, along with IPv6 and UNIX socket formats.

```nginx
listen 127.0.0.1:8000;
listen 127.0.0.1;
listen 8000;
listen *:8000;
listen localhost:8000;
listen [::]:8000;
listen [::1];
listen unix:/var/run/angie.sock;
```

--------------------------------

### Cloud-Init User-Data Example

Source: https://angie.software/adc/docs/install/cloud-init/install-qcow2-0.5

Basic structure for the user-data file in a cloud-init ISO image. The content is minimal, primarily serving as a placeholder.

```yaml
#cloud-config
{}

```

--------------------------------

### Nginx Proxy Configuration Example for Storing Images

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http_proxy

An example Nginx configuration demonstrating how to store proxied images locally using proxy_store, proxy_store_access, and proxy_temp_path directives. It includes error page handling for fetching missing images.

```nginx
location /images/ {
    root               /data/www;
    error_page         404 = /fetch$uri;
}

location /fetch/ {
    internal;

    proxy_pass         http://backend/;
    proxy_store        on;
    proxy_store_access user:rw group:rw all:r;
    proxy_temp_path    /data/temp;

    alias              /data/www/;
}
```

--------------------------------

### Nginx try_files Directive Examples

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http

Demonstrates the use of the try_files directive in Nginx to check for file existence and serve the first found file, or fall back to a URI or error code. Includes examples for serving images, handling 404 errors, and integrating with PHP, Drupal, WordPress, and Joomla.

```nginx
location /images/ {
  try_files $uri /images/default.gif;
}

location = /images/default.gif {
  expires 30s;
}
```

```nginx
location / {
  try_files $uri $uri/index.html $uri.html =404;
}
```

```nginx
location / {
  error_page 404 = @drupal;
  log_not_found off;
}
```

```nginx
location ~ \.php$ {
  try_files $uri @drupal;

  fastcgi_pass ...;

  fastcgi_param SCRIPT_FILENAME /path/to$fastcgi_script_name;

#  ...
}
```

```nginx
location / {
  try_files /system/maintenance.html
           $uri $uri/index.html $uri.html
           @mongrel;
}

location @mongrel {
  proxy_pass http://mongrel;
}
```

```nginx
location / {
  error_page 404 = @drupal;
}

location ~ \.php$ {
  try_files $uri @drupal;

  fastcgi_pass ...;

  fastcgi_param SCRIPT_FILENAME /path/to$fastcgi_script_name;
  fastcgi_param SCRIPT_NAME     $fastcgi_script_name;
  fastcgi_param QUERY_STRING    $args;

#  ... прочие fastcgi_param
}

location @drupal {
  fastcgi_pass ...;

  fastcgi_param SCRIPT_FILENAME /path/to/index.php;
  fastcgi_param SCRIPT_NAME     /index.php;
  fastcgi_param QUERY_STRING    q=$uri&$args;

#  ... прочие fastcgi_param
}
```

```nginx
location / {
  error_page 404 = @wordpress;
}

location ~ \.php$ {
  try_files $uri @wordpress;

  fastcgi_pass ...;

  fastcgi_param SCRIPT_FILENAME /path/to$fastcgi_script_name;
#  ... прочие fastcgi_param
}

location @wordpress {
  fastcgi_pass ...;

  fastcgi_param SCRIPT_FILENAME /path/to/index.php;
#  ... прочие fastcgi_param
}
```

--------------------------------

### Angie ADC 'groups' Configuration Example

Source: https://angie.software/adc/docs/gslb/reference

This example demonstrates how to define server groups using the 'groups' directive in Angie ADC configuration. It shows how to create a 'www' group containing individual servers and another group 'www3' that includes individual servers and the previously defined 'www' group. This facilitates reuse of server configurations across different contexts.

```yaml
groups:
  www:
    members:
      - server: www1
      - server: www2
  www3:
    members:
      - server: www4
      - server: www5
      - group: www

```

--------------------------------

### Example Upstream Configuration

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http_api

This is an example of an 'upstream' block in Angie configuration. It defines a backend server group with a shared memory zone and lists specific servers with their resolution and service discovery details.

```nginx
upstream backend {
    server backend.example.com service=_http._tcp resolve;
    server 127.0.0.1;
    zone backend 1m;
}

```

--------------------------------

### Angie ADC Mail Module Configuration Example

Source: https://angie.software/adc/docs/configuration_lb/reference/mail/mail

This example demonstrates a basic configuration for the Angie ADC mail module, setting up worker processes, logging, event handling, and defining mail server blocks for SMTP, POP3, and IMAP protocols. It includes authentication methods and capabilities for each protocol.

```nginx
worker_processes auto;

error_log /var/log/angie/error.log info;

events {
    worker_connections  1024;
}

mail {
    server_name       mail.example.com;
    auth_http         localhost:9000/cgi-bin/auth.cgi;

    imap_capabilities IMAP4rev1 UIDPLUS IDLE LITERAL+ QUOTA;

    pop3_auth         plain apop cram-md5;
    pop3_capabilities LAST TOP USER PIPELINING UIDL;

    smtp_auth         login plain cram-md5;
    smtp_capabilities "SIZE 10485760" ENHANCEDSTATUSCODES 8BITMIME DSN;
    xclient           off;

    server {
        listen   25;
        protocol smtp;
    }
    server {
        listen   110;
        protocol pop3;
        proxy_pass_error_message on;
    }
    server {
        listen   143;
        protocol imap;
    }
    server {
        listen   587;
        protocol smtp;
    }
}


```

--------------------------------

### Example Remote Storage HTTP Response

Source: https://angie.software/adc/docs/configuration_lb/reference/stream/stream_upstream

This example shows a typical HTTP response from a remote storage service. A 200 OK status with specific headers like 'X-Sticky-Sid' and 'X-Session-Info' is used to confirm server selection and provide session details.

```http
HTTP/1.1 200 OK
...
X-Sticky-Sid: backend-01
X-Session-Info: active


```

--------------------------------

### HTTP/3 and QUIC Server Configuration Example

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http_v3

This example demonstrates how to configure an Nginx server block to support HTTP/3 over QUIC and TLS. It includes settings for the access log format, listen directives for both QUIC and SSL, certificate paths, and enabling the Alt-Svc header for HTTP/3 advertisement. Requires OpenSSL 1.1.1+ for TLSv1.3.

```nginx
http {
    log_format quic '$remote_addr - $remote_user [$time_local] ' 
                    '"$request" $status $body_bytes_sent ' 
                    '"$http_referer" "$http_user_agent" "$http3"';

    access_log logs/access.log quic;

    server {
        # для лучшей совместимости рекомендуется
        # использовать одинаковый порт для http/3 и https
        listen 8443 quic reuseport;
        listen 8443 ssl;

        ssl_certificate     certs/example.com.crt;
        ssl_certificate_key certs/example.com.key;

        location / {
            # используется для объявления о поддержке http/3
            add_header Alt-Svc 'h3=":8443"; ma=86400';
        }
    }
}
```

--------------------------------

### split_clients Directive Example (Nginx Configuration)

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http_split_clients

This example demonstrates the usage of the split_clients directive to distribute clients based on the hashed value of a string. It defines buckets for '.one', '.two', and a default empty string, with specified percentage allocations.

```nginx
split_clients "${remote_addr}AAA" $variant {
               0.5%               .one;
               2.0%               .two;
               *                  "";
}
```

--------------------------------

### Deploy Angie ADC VM with virt-install

Source: https://angie.software/adc/docs/install/cloud-init/install-qcow2-0.5

Launches a KVM virtual machine for Angie ADC using virt-install. It configures RAM, vCPUs, disk image, the cloud-init ISO as a CD-ROM, network bridge, and graphics settings.

```bash
virt-install \
  --virt-type kvm \
  --name adc \
  --ram 2048 \
  --vcpus 2 \
  --disk angie-adc-0.5.2-x86_64.cloud-init.qcow2,format=qcow2 \
  --disk seed.iso,device=cdrom \
  --network=bridge:virbr0 \
  --graphics vnc,listen=0.0.0.0 \
  --os-variant=centos8 \
  --import

```

--------------------------------

### Limit HTTP Methods within a Location (Nginx)

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http

The `limit_except` directive restricts the HTTP methods that are allowed within a specific location block. Methods like `GET`, `POST`, `PUT`, etc., can be specified. If `GET` is allowed, `HEAD` is implicitly allowed. Other access restrictions can be managed using `allow` and `deny` directives or authentication modules. The example shows restricting access to all methods except GET and HEAD.

```nginx
location / { 
  limit_except GET {
    allow 192.168.1.0/32;
    deny  all;
  }
}
```

--------------------------------

### DNS Configuration for ACME Challenge

Source: https://angie.software/adc/docs/configuration_lb/reference/acme

Example DNS records required to delegate DNS resolution for the `_acme-challenge.` subdomain to a specific nameserver. This setup is necessary for ACME DNS-01 validation.

```dns
_acme-challenge.example.com. 60    IN      NS       ns.example.com.
             ns.example.com. 60    IN       A       93.184.215.14

```

--------------------------------

### Get TLV data from PROXY protocol header

Source: https://angie.software/adc/docs/configuration_lb/reference/stream/stream

Retrieves TLV (Tag-Length-Value) data from the PROXY protocol header. The name can be a TLV type name or its numeric value (hexadecimal, starting with 0x). SSL TLVs are also supported with names starting with 'ssl_'. The PROXY protocol must be enabled. This is a built-in variable available in the stream context.

```nginx
$proxy_protocol_tlv_<name>
```

--------------------------------

### Nginx HTTP Server Configuration with API Location

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http_api

Example Nginx HTTP server configuration that includes a location block for the '/config/' API. This setup restricts access to the API to localhost.

```nginx
http {
    # ...

    upstream backend {
        zone upstream 256k;
        server backend.example.com resolve max_conns=5;
        # ...
    }

    server {
        # ...

        location /config/ {
            api /config/;

            allow 127.0.0.1;
            deny all;
        }
    }
}
```

--------------------------------

### Create Cloud-Init ISO Image

Source: https://angie.software/adc/docs/install/cloud-init/install-qcow2-0.5

Generates a bootable ISO image named 'seed.iso' containing the prepared 'meta-data', 'user-data', and 'network-config' files. This ISO is used by cloud-init for VM initialization.

```bash
genisoimage -output seed.iso -volid cidata -joliet -rock meta-data user-data network-config

```

--------------------------------

### Example: Listing Available Certificates and Keys

Source: https://angie.software/adc/docs/management/cli-commands

Shows the output of the `list` command in the `cert-config` context, which displays available certificate and key files and their validation status.

```cli
(cert-config)$$ list
cp.crt   : invalid
cp.key   : invalid
site1.crt: certificate
site1.key: key

```

--------------------------------

### TCP/UDP Upstream Probe Configuration Example

Source: https://angie.software/adc/docs/configuration_lb/health-probes

This example shows how to configure a TCP/UDP upstream probe. It details the setup for upstream servers, a map for probe response checking, and the `upstream_probe` directive with parameters for port, interval, test condition, essentiality, persistence, failure/success counts, max response size, mode, and send data. It also notes the requirement for CRLF separators in HTTP headers.

```nginx
upstream backend {
    zone backend 1m;

    server a.example.com;
    server b.example.com;
}

map $upstream_probe_response $good {
    ~200    "1";
    default  "";
}

server {
    listen ...;

    # ...
    proxy_pass backend;
    upstream_probe_timeout 1s;

    upstream_probe backend_probe
        port=12345
        interval=5s
        test=$good
        essential
        persistent
        max_response=512k
        mode=onfail
        "send=data:GET / HTTP/1.0\r\n\r\n";
}
```

--------------------------------

### Example: Matching Certificate and Key Files

Source: https://angie.software/adc/docs/management/cli-commands

Illustrates the usage of the `match` command to verify if a given certificate file and key file are a valid pair. It shows successful and unsuccessful matching scenarios.

```cli
(cert-config)$$ match site1.crt site1.key
Certificate and key match
(cert-config)$$ match site1.crt site2.key
Certificate and key DO NOT match
(cert-config)$$

```

--------------------------------

### Certbot Nginx Configuration Example

Source: https://angie.software/adc/docs/configuration_lb/reference/acme

An example of a typical Nginx server block configuration generated by certbot for handling HTTP and HTTPS traffic, including SSL certificate paths.

```nginx
server {

    listen 80;
    server_name example.com www.example.com;
    return 301 https://$host$request_uri;
}

server {

    listen 443 ssl;
    server_name example.com www.example.com;

    root /var/www/example;
    index index.html;

    ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
    include /etc/letsencrypt/options-ssl-nginx.conf;
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
}

```

--------------------------------

### Nginx Location Matching Examples

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http

Demonstrates various ways to define Nginx 'location' blocks using prefix strings, exact matches, regular expressions, and named locations. It illustrates how different request URIs are matched to specific configurations.

```nginx
location =/ {
   #конфигурация А
}

location / {
   #конфигурация Б
}

location /documents/ {
   #конфигурация В
}

location ^~/images/ {
   #конфигурация Г
}

location ~*\.(gif|jpg|jpeg)$ {
   #конфигурация Д
}

```

```nginx
location /user/ {
  proxy_pass http://user.example.com;
}

location =/user {
  proxy_pass http://login.example.com;
}

```

--------------------------------

### Проверка состояния виртуальной сети

Source: https://angie.software/adc/docs/install/install-qcow2

Команда для проверки списка активных виртуальных сетей libvirt. Используется для диагностики сетевых проблем перед развертыванием.

```bash
sudo virsh net-list --all
```

--------------------------------

### Convert HEAD to GET for Caching (Nginx Configuration)

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http_proxy

Enables or disables the conversion of the 'HEAD' method to 'GET' for caching purposes. If disabled, the cache key must include the $request_method variable.

```nginx
proxy_cache_convert_head on;
```

--------------------------------

### ICMP Echo Request Probe Configuration Example

Source: https://angie.software/adc/docs/configuration_lb/health-probes

This example illustrates using ICMP Echo requests for upstream probing instead of traditional HTTP requests. It configures an upstream block with server IP addresses and then uses the `upstream_probe` directive with the `ping` option. The example highlights how ICMP checks availability of the IP address, ignoring ports, and specifies different timeout values for probe responses.

```nginx
http {
    upstream u {
        zone z 1k;

        server 127.0.0.1:8081;
        server 127.0.0.1:8082;
    }

    server {
        listen ...;

        location / {
            proxy_pass http://u/;

            upstream_probe simple1
                 interval=3s
                 ping;

            upstream_probe simple2
                 interval=3s
                 ping ping_timeout=3s;
        }
    }

}
```

--------------------------------

### Configuring Listen Socket Options (Angie)

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http

Demonstrates the use of optional parameters within the 'listen' directive to control socket behavior. This includes setting default servers, enabling SSL, HTTP/2, QUIC, and proxy protocol, as well as fine-tuning socket parameters.

```nginx
listen 80 default_server ssl http2;
listen 443 ssl spdy;
listen 9000 quic reuseport;
listen 10000 proxy_protocol;
listen 10001 backlog=1024;
listen 10002 rcvbuf=128k sndbuf=128k;
listen 10003 accept_filter=dataready;
listen 10004 deferred;
listen 10005 reuseport so_keepalive=on;
listen 10006 ipv6only=on;
```

--------------------------------

### Nginx Upstream Configuration Example

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http_api

An example of Nginx stream upstream configuration, defining a 'backend' upstream with multiple servers and a 'zone' for shared memory. This configuration is relevant for the API endpoints described.

```nginx
upstream backend {
    server backend.example.com:8080 service=_example._tcp resolve;
    server 127.0.0.1:12345;
    zone backend 1m;
}

upstream backend {
    zone backend 256k;
    server backend.example.com resolve max_conns=5;
    random;
}
```

--------------------------------

### Prometheus Configuration Example

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http_prometheus

This snippet shows how to include Prometheus configuration and define a server block with a location that exposes metrics in Prometheus format. It assumes `prometheus_all.conf` is included and sets up a listener on port 80 for the `/p8s` path.

```nginx
http {

    include prometheus_all.conf;

    # ...

    server {

        listen 80;

        location =/p8s {
            prometheus all;
        }

        # ...

    }
}
```

--------------------------------

### MP4 Pseudo-Streaming with Start and End Times

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http_mp4

Illustrates how to use both 'start' and 'end' query parameters to define a specific playback range for an MP4 file. This enables clients to request a segment of the video.

```http
http://example.com/elephants_dream.mp4?start=238.88&end=555.55
```

--------------------------------

### Развертывание Angie ADC ВМ

Source: https://angie.software/adc/docs/install/install-qcow2

Команды для перемещения образа Angie ADC и запуска виртуальной машины с помощью virt-install. Требует наличия образа qcow2 и указания параметров ВМ.

```bash
sudo mv angie-adc-0.6.0-x86_64.cloud-init.qcow2 /var/lib/libvirt/images/
sudo virt-install  --name angie-adc-0.6.0 --ram 2048 --disk /var/lib/libvirt/images/angie-adc-0.6.0-x86_64.cloud-init.qcow2 --os-variant generic --import
```

--------------------------------

### Example: Displaying Certificate Information

Source: https://angie.software/adc/docs/management/cli-commands

Demonstrates how to view detailed information about a traffic certificate named 'site1.crt' using the `info` command within the `cert-config` context.

```cli
(cert-config)$$ info traffic name site1.crt
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number: 1 (0x1)
        Signature Algorithm: sha1WithRSAEncryption
        Issuer: C = RU, ST = Moscow, O = Angie, OU = EVO, CN = Root CA
        Validity
            Not Before: Feb 18 12:23:08 2025 GMT
            Not After : Feb 18 12:23:08 2027 GMT
        Subject: CN = Demo Certificate, ST = Moscow, C = RU, O = Angie, OU = EVO
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (4096 bit)
                Modulus:
...
(cert-config)$$

```

--------------------------------

### Stream Limit Conn Configuration Example

Source: https://angie.software/adc/docs/monitoring-and-statistics/console-light

This example demonstrates the configuration of `limit_conn_zone` and `limit_conn` directives within the `stream` context for controlling connection limits. It requires `status_zone` and `limit_conn` directives in the `server` context, and `limit_conn_zone` in the `stream` context.

```nginx
stream {

    # ...
    limit_conn_zone $connection zone=limit-conn-stream:10m;

    server {

        # ...
        limit_conn limit-conn-stream 1;
        status_zone foo;
    }
}


```

--------------------------------

### Add User to Libvirt and KVM Groups

Source: https://angie.software/adc/docs/install/cloud-init/install-qcow2-0.5

Adds the current user to the 'libvirt' and 'kvm' groups to grant necessary permissions for managing virtual machines. This is a crucial step after installing virtualization software.

```bash
$ sudo usermod -aG libvirt USER
$ sudo usermod -aG kvm USER

```

--------------------------------

### Geo Module Configuration Example

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http_geo

The geo module creates variables whose values depend on the client's IP address. This example demonstrates how to define IP address ranges and assign values to a variable named $geo.

```nginx
geo $geo {
    default        0;

    127.0.0.1      2;
    192.168.1.0/24 1;
    10.1.0.0/16    1;

    ::1            2;
    2001:0db8::/32 1;
}

```

--------------------------------

### Get Stream Upstream Server Configuration

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http_api

Retrieves configuration for a specific server within a stream upstream. Supports fetching individual parameters or the entire server configuration. The `defaults=on` argument can be used to get default parameter values.

```bash
$ curl http://127.0.0.1/config/http/upstreams/backend/servers/backend.example.com/max_conns
$ curl http://127.0.0.1/config/http/upstreams/backend/servers/backend.example.com
$ curl http://127.0.0.1/config/http/upstreams/backend/servers
$ curl http://127.0.0.1/config/http/upstreams/backend/servers?defaults=on
```

--------------------------------

### Basic HTTP Load Balancing with Round-Robin (Angie ADC)

Source: https://angie.software/adc/docs/configuration_lb/lb-methods

This example demonstrates the simplest HTTP load balancing configuration using Angie ADC. It sets up an upstream group 'myapp1' with three servers and distributes incoming requests on port 80 using the default round-robin method.

```nginx
http {

    upstream myapp1 {

        server srv1.example.com;
        server srv2.example.com;
        server srv3.example.com;
    }
    server {

        listen 80;
        location / {

            proxy_pass http://myapp1;
        }
    }
}
```

--------------------------------

### Add User to Libvirt and KVM Groups

Source: https://angie.software/adc/docs/install/install-qcow2

Adds the current user to the 'libvirt' and 'kvm' groups, granting them necessary permissions to manage virtual machines and interact with QEMU/KVM. Replace 'USER' with your actual username.

```bash
sudo usermod -aG libvirt USER
sudo usermod -aG kvm USER

```

--------------------------------

### Configure network-config for OVA with E1000 driver (cloud-init)

Source: https://angie.software/adc/docs/install/cloud-init/install-cloud-init

This snippet demonstrates how to configure static IP addresses, gateways, and DNS settings for multiple network interfaces (ens33, ens37, ens38) on an OVA image using cloud-init. It assumes the E1000 network driver. If DHCP is used, the network-config file can be left empty.

```yaml
#cloud-config
network:
  version: 2
  ethernets:
    ens33:
      dhcp4: false
      addresses:
        - 192.168.100.155/24
      gateway4: 192.168.100.1
      nameservers:
        addresses: [8.8.8.8, 1.1.1.1]
        search: [example.com]
    ens37:
      dhcp4: false
      addresses:
        - 192.168.110.155/24
      gateway4: 192.168.110.1
      nameservers:
        addresses: [8.8.8.8, 1.1.1.1]
        search: [example.com]
    ens38:
      dhcp4: false
      addresses:
        - 192.168.120.155/24
      gateway4: 192.168.120.1
      nameservers:
        addresses: [8.8.8.8, 1.1.1.1]
        search: [example.com]

```

--------------------------------

### Define Character Set Mapping Table (Nginx/Angie Config)

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http_charset

The `charset_map` directive describes a conversion table from one character set to another. Character codes are specified in hexadecimal. The example shows mapping from `koi8-r` to `windows-1251` and `utf-8`, with provided example files for full transformations.

```nginx
charset_map koi8-r windows-1251 {
    C0 FE ;
    C1 E0 ;
    C2 E1 ;
    C3 F6 ;
}

charset_map koi8-r utf-8 {
    C0 D18E ;
    C1 D0B0 ;
    C2 D0B1 ;
    C3 D186 ;
}
```

--------------------------------

### Configure Access Logging with Buffering and Gzip Compression

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http_log

This example demonstrates configuring the access_log directive to write to a compressed log file with buffering and a flush interval. It requires the zlib library for gzip support and specifies the log path, format, gzip compression level, and flush time.

```nginx
access_log /path/to/log.gz combined gzip flush=5m;

```

--------------------------------

### Angie ADC Configuration File Structure

Source: https://angie.software/adc/docs/configuration_lb/reference/configfile

Demonstrates the hierarchical structure of an Angie ADC configuration file, including the main, events, http, and stream contexts, as well as server and location blocks within the http context. It also shows example directives.

```nginx
user angie; # директива в контексте 'main'

events {

    # конфигурация обработки соединений
}

http {

    # Конфигурация трафика HTTP, для всех вложенных виртуальных серверов

    server {

        # конфигурация виртуального HTTP сервера 1
        location /one {

            # конфигурация обработки HTTP запросов с URI, начинающимися с '/one'
        }
        location /two {

            # конфигурация обработки HTTP запросов с URI, начинающимися с '/two'
        }
    }

    server {

        # конфигурация виртуального HTTP сервера 2
    }
}

stream {

    # Конфигурация трафика TCP/UDP, для всех вложенных виртуальных серверов
    server {

        # конфигурация виртуального TCP сервера 1
    }
}

```

--------------------------------

### Get hostname

Source: https://angie.software/adc/docs/configuration_lb/reference/stream/stream

Represents the hostname. This is a built-in variable available in the stream context.

```nginx
$hostname
```

--------------------------------

### Configure Server Names with Wildcards and Regex - Nginx

Source: https://angie.software/adc/docs/configuration_lb/reference/stream/stream

This snippet demonstrates configuring server names using exact matches, wildcards (*), and regular expressions (~) in Nginx. It covers basic server name definition, wildcard usage for subdomains and partial matches, and regex for complex pattern matching, including named capture groups.

```nginx
server {
    listen 443 ssl;
    server_name example.com www.example.com;
    ssl_certificate /etc/angie/cert.pem;
    ssl_certificate_key /etc/angie/key.pem;
}

server {
    server_name example.com *.example.com www.example.*;
}

server {
    server_name www.example.com ~^www\d+\.example\.com$;
}

server {
    server_name ~^(www\.)?(.+)$; 
    proxy_pass www.$2:12345;
}

server {
    server_name ~^(www\.)?(?<domain>.+)$; 
    proxy_pass www.$domain:12345;
}
```

--------------------------------

### Get Angie version

Source: https://angie.software/adc/docs/configuration_lb/reference/stream/stream

Represents the version of Angie. This is a built-in variable available in the stream context.

```nginx
$angie_version
```

--------------------------------

### Geo Module Syntax and Basic Usage

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http_geo

Demonstrates the fundamental syntax of the 'geo' module, including how to specify an address source and a variable to store the result. It also shows how to reference external configuration files.

```nginx
geo $arg_remote_addr $geo {
    ...
}
```

```nginx
geo $country {
    default        ZZ;
    include        conf/geo.conf;
    delete         127.0.0.0/16;
    proxy          192.168.100.0/24;
    proxy          2001:0db8::/32;

    127.0.0.0/24   US;
    127.0.0.1/32   RU;
    10.1.0.0/16    RU;
    192.168.1.0/24 UK;
}
```

```nginx
10.2.0.0/16    RU;
192.168.2.0/24 RU;
```

--------------------------------

### Configure FLV Module for Pseudo-Streaming

Source: https://angie.software/adc/docs/configuration_lb/reference/http/http_flv

Enables server-side support for pseudo-streaming of Flash Video (FLV) files. It handles requests with a 'start' argument by sending file content from the specified byte offset, prepended with an FLV header. The module needs to be compiled with `--with-http_flv_module` or is included in pre-built packages.

```nginx
location ~ \.flv$ {
    flv;
}
```

--------------------------------

### Get client port

Source: https://angie.software/adc/docs/configuration_lb/reference/stream/stream

Represents the client's port. This is a built-in variable available in the stream context.

```nginx
$remote_port
```