Allocate and Bind EIP to Existing Cloud Resources

Scenario Description

Allocate Elastic IP Address (EIP) and bind it to existing Alibaba Cloud resources for public internet access. This skill focuses on EIP product capabilities only. Supported Resource Types:

• EcsInstance: ECS instance (requires instance ID)
• NetworkInterface: Elastic Network Interface/ENI (requires ENI ID + private IP address)
• SlbInstance: Classic Load Balancer/CLB (requires CLB instance ID)
• Nat: NAT Gateway (requires NAT Gateway ID)
• HaVip: High-Availability Virtual IP (requires HaVip ID)
• IpAddress: Direct IP address binding (requires VPC ID + IP address) Key Principles:

1. ✅ Only operate on user-provided resource IDs - never query or auto-select resources
2. ✅ Fail fast - stop immediately on unrecoverable errors
3. ✅ No resource creation - only bind to existing resources (no new ECS/NAT/VPC creation)
4. ✅ User confirmation - ask for key EIP parameters before allocation
5. ✅ Cleanup on failure - release newly allocated EIPs if binding fails

Pre-checks

1. Aliyun CLI version verification (>= 3.3.3)

Pre-check: Aliyun CLI >= 3.3.3 required

Run aliyun version to verify >= 3.3.3. If not installed or version too low, run curl -fsSL https://aliyuncli.alicdn.com/setup.sh | bash to update, or see references/cli-installation-guide.md for installation instructions.

Pre-check: Aliyun CLI plugin update required

[MUST] run aliyun configure set --auto-plugin-install true to enable automatic plugin installation. [MUST] run aliyun plugin update to ensure that any existing plugins are always up-to-date.

aliyun configure set --auto-plugin-install true
CLI_VERSION=$(aliyun version 2>/dev/null | grep -oE '[0-9]+\.[0-9]+\.[0-9]+' | head -1)
[ "$(printf '%s\
' "3.3.3" "$CLI_VERSION" | sort -V | head -n1)" != "3.3.3" ] && echo "❌ CLI \x3C 3.3.3" && exit 1
aliyun plugin update

2. Authentication credential verification

aliyun configure list  # Check valid profile (AK/STS/OAuth). NEVER echo AK/SK.

Workflow Overview

Key rules for ALL commands below: [MUST] CLI User-Agent — Every aliyun CLI command invocation must include: --user-agent AlibabaCloud-Agent-Skills/alibabacloud-network-eip-associate

• Every aliyun product command MUST include --user-agent AlibabaCloud-Agent-Skills/alibabacloud-network-eip-associate (NOT on configure commands)
• Use plugin mode (kebab-case): aliyun vpc allocate-eip-address, NOT AllocateEipAddress
• VPC commands require --biz-region-id \x3CRegion>
• CRITICAL: --biz-region-id only sets the RegionId parameter in the API request body; it does NOT control which API endpoint the CLI connects to. The API endpoint is determined by the CLI profile's configured region. Before running any VPC command, you MUST set the CLI profile region to match the target region:

  aliyun configure set --region {REGION}
  

• jq is NOT available — use grep to parse JSON output Global Variables to Track:
• CREATED_EIPS: Array of EIP AllocationIds created in this session (for user-controlled cleanup on failure)
• REGION: Target region (MUST be explicitly provided by user, no default)
• INSTANCE_TYPE: Target resource type (EcsInstance/NetworkInterface/SlbInstance/Nat/HaVip/IpAddress)
• USE_EXISTING_EIP: Boolean flag (true = use existing EIP, false = create new EIP)
• ALLOCATION_ID: EIP instance ID (from existing EIP or newly allocated)

Workflow Phases:

1. Phase 1: Extract user input, validate resource, choose existing/new EIP
   • Steps 1.1-1.2: Extract parameters, set CLI region
   • Step 1.3: Check if resource already has EIP bound (DescribeEipAddresses)
   • Step 1.3.5: Check if ECS has PIP/Public IP (ECS only, DescribeInstanceAttribute)
   • Step 1.4: User chooses existing EIP or new EIP
   • Step 1.5: Use existing EIP (query available EIPs, let user select)
   • Step 1.6: Create new EIP (confirm parameters)
   • Step 1.7: Pre-allocation validation (only for new EIP)
2. Phase 2: Allocate EIP (only if USE_EXISTING_EIP = false)
3. Phase 3: Bind EIP to target resource (actual execution)
4. Phase 4: Verify binding
5. Phase 5: Cleanup on failure (ask user to keep or release newly created EIP)

Phase 1: Extract User Input and Validate Resource

Step 1.1: Extract required parameters from user message

Required from user:

• Region: Target region (e.g., cn-beijing, cn-hangzhou) - MUST be explicitly provided, no default
• Resource Type: One of: ECS / ENI / CLB / NAT / HAVIP / IP
• Resource ID: Exact instance ID, ENI ID, NAT ID, etc.
• Additional parameters (instance-type specific):
  • If NetworkInterface: Must have PrivateIpAddress (private IP to bind)
  • If IpAddress: Must have VpcId (VPC ID where IP address resides) If ANY required parameter is missing, STOP and ask user: ❌ Missing: Region[REQUIRED] | ResourceType[ECS/ENI/CLB/NAT/HAVIP/IP] | ResourceID | [PrivateIP for ENI] | [VpcId for IP] CRITICAL:
• Region MUST be explicitly provided by user. Do NOT use default region (like cn-hangzhou).
• Do NOT proceed without explicit user-provided values.

Step 1.1.1: Input Validation (Security)

Validate inputs to prevent command injection:

• Region: ^[a-z]{2,3}-[a-z]+-\d*[a-z]*$ (e.g., cn-beijing, ap-southeast-1)
• Resource IDs: ^(i|eni|lb|ngw|havip|eip|vpc)-[a-z0-9]+$
• IP Address: ^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$ If validation fails, STOP: ❌ Invalid input format

Step 1.2: Set CLI region to target region

Before any API operation, configure CLI region:

aliyun configure set --region {REGION}

This ensures the CLI connects to the correct regional API endpoint.

Step 1.3: Check if resource already has EIP bound

Use DescribeEipAddresses to check if the target resource already has an EIP: Map user input to InstanceType parameter:

aliyun vpc describe-eip-addresses \
  --biz-region-id {REGION} \
  --associated-instance-type {INSTANCE_TYPE} \
  --associated-instance-id {RESOURCE_ID} \
  --user-agent AlibabaCloud-Agent-Skills/alibabacloud-network-eip-associate

Check response: If TotalCount > 0 (resource already has EIP bound):

❌ ERROR: Resource {RESOURCE_ID} already has EIP bound.
Existing EIP: {EipAddress} | ID: {AllocationId} | Bandwidth: {Bandwidth}Mbps | Status: {Status}
To bind a different EIP, first unbind existing: aliyun vpc unassociate-eip-address --biz-region-id {REGION} --allocation-id {AllocationId} --instance-id {RESOURCE_ID} --instance-type {INSTANCE_TYPE}

STOP. If TotalCount = 0 (resource has no EIP bound):

✅ Resource {RESOURCE_ID} has no EIP bound. Proceeding to next validation...

Continue to Step 1.3.5.

Step 1.3.5: Check if ECS instance has PIP (Public IP) - ECS Only

This step is ONLY executed when INSTANCE_TYPE = EcsInstance. For other resource types (ENI, CLB, NAT, HAVIP, IP), skip directly to Step 1.4. Purpose: Check if the ECS instance already has a Public IP (PIP) assigned at creation time. PIP is different from EIP:

• EIP (Elastic IP): Can be dynamically bound/unbound to resources
• PIP (Public IP): Fixed public IP assigned when ECS is created, released when ECS is deleted, cannot be unbound Query command:

aliyun ecs describe-instance-attribute \
  --instance-id {RESOURCE_ID} \
  --user-agent AlibabaCloud-Agent-Skills/alibabacloud-network-eip-associate

Parse response and check PublicIpAddress field: Case 1: PublicIpAddress.IpAddress is not empty (ECS has PIP):

❌ ERROR: ECS instance {RESOURCE_ID} already has a Public IP (PIP) assigned.
Public IP: {PublicIpAddress.IpAddress[0]} | Type: PIP (fixed, created with ECS)

⚠️ You CANNOT bind an EIP to an ECS instance that already has a PIP.
Options:
1. Use the existing Public IP (no action needed)
2. Convert PIP to EIP (requires ECS Stopped): aliyun vpc convert-nat-public-ip-to-eip --biz-region-id {REGION} --instance-id {RESOURCE_ID}
3. Release and recreate ECS without PIP
Operation stopped.

STOP. Case 2: PublicIpAddress.IpAddress is empty (no PIP):

✅ ECS instance {RESOURCE_ID} has no Public IP (PIP). Ready to bind EIP.

Continue to Step 1.4. Case 3: API call fails (e.g., InvalidInstanceId.NotFound):

❌ ERROR: ECS instance {RESOURCE_ID} not found in region {REGION}.
Error: {ERROR_CODE} - {ERROR_MESSAGE}
Please verify: instance ID, region, and permissions.

STOP.

Step 1.4: Choose between existing EIP or new EIP

Options for {RESOURCE_TYPE} {RESOURCE_ID}:
A) Use existing EIP (query available or provide ID)
B) Create new EIP (configure bandwidth, ISP, billing)
Choice (A/B):

If user selects Option A (use existing EIP), proceed to Step 1.5. If user selects Option B (create new EIP), proceed to Step 1.6.

Step 1.5: Use Existing EIP (Option A)

Step 1.5.1: Ask if user has specific EIP ID

Have specific EIP ID? (yes: provide ID / no: query available)

If user provides EIP ID:

• Save as ALLOCATION_ID
• Validate EIP exists and is Available (query with DescribeEipAddresses)
• If EIP not found or not Available, show error and ask again
• Skip to Phase 3 (bind existing EIP) If user wants to see available EIPs, proceed to Step 1.5.2.

Step 1.5.2: Query available EIPs

Query all Available EIPs in the region:

aliyun vpc describe-eip-addresses \
  --biz-region-id {REGION} \
  --status Available \
  --page-size 100 \
  --user-agent AlibabaCloud-Agent-Skills/alibabacloud-network-eip-associate

Handle pagination if needed:

• If TotalCount > 100, make multiple requests with --page-number 2, 3, ... until all Available EIPs are retrieved
• Collect all Available EIPs across all pages If no available EIPs found (TotalCount = 0):

❌ No available EIPs in {REGION}. Create new EIP? (yes/no)

If user says yes, go to Step 1.6. If no, STOP. If available EIPs found:

Step 1.5.3: Present available EIPs to user

If 5 or fewer: Show all. If >5: Show 5 random.

Found {TOTAL_COUNT} available EIP(s) in {REGION}:
1. eip-bp1xxx | 47.1.2.3 | 5Mbps | BGP | PayByTraffic
2. eip-bp1yyy | 47.4.5.6 | 10Mbps | BGP | PayByBandwidth
...
Select: Enter number (1-5), EIP ID, or "new" for new EIP:

Wait for user selection. Validate user selection:

• If user enters number: Map to corresponding EIP from the list
• If user enters EIP ID: Validate it's in the Available state
• If user types "new": Go to Step 1.6
• If invalid input: Ask again Save selected EIP's AllocationId. Set USE_EXISTING_EIP = true (to skip EIP allocation in Phase 2). Skip to Phase 3 (bind existing EIP).

Step 1.6: Create New EIP (Option B)

Ask user for EIP configuration:

Create new EIP in {REGION} for {RESOURCE_TYPE} {RESOURCE_ID}.
Config (Enter for defaults): Bandwidth[5Mbps] | ISP[BGP/BGP_PRO] | Billing[PayByTraffic/PayByBandwidth] | Purpose[optional for naming]

Defaults: BANDWIDTH=5, ISP=BGP, INTERNET_CHARGE_TYPE=PayByTraffic EIP Naming: If purpose provided, generate name: eip-{purpose}-{resource_type} (e.g., eip-web-ecs) Set USE_EXISTING_EIP = false (will allocate new EIP in Phase 2). IMPORTANT: Always create PayByTraffic (pay-by-traffic) EIP by default unless user explicitly requests PayByBandwidth. IMPORTANT: PrePaid (subscription/包年包月) EIP is NOT supported by this skill. If user requests PrePaid EIP, respond:

❌ This skill does not support creating PrePaid (subscription) EIPs.
Please create PrePaid EIPs through the Alibaba Cloud Console: https://vpc.console.aliyun.com/eip

STOP. Continue to Phase 1.7 (pre-allocation validation) if creating new EIP.

Step 1.7: Pre-Allocation Validation (Only for New EIP)

This step is ONLY executed when USE_EXISTING_EIP = false (creating new EIP). If using existing EIP, skip directly to Phase 3.

Step 1.7.1: Check EIP quota

Query EIP count: aliyun vpc describe-eip-addresses --biz-region-id {REGION} --page-size 100 If approaching 20 (standard limit), show quota warning. This is a soft check.

Step 1.7.2: Validate target resource (best-effort)

For EcsInstance: aliyun ecs describe-instances --instance-ids '["ID"]'

• Status != Running/Stopped: warning
• PublicIpAddress non-empty: STOP (PIP conflict) For NetworkInterface (ENI): aliyun ecs describe-network-interfaces --network-interface-id '["ID"]'
• Validate PrivateIpAddress exists in PrivateIpSets. STOP if not found. For SlbInstance (CLB): aliyun slb describe-load-balancer-attribute --load-balancer-id ID
• AddressType=internet: STOP (PIP conflict). AddressType=intranet: proceed. For Nat: aliyun vpc describe-nat-gateways --nat-gateway-id ID For HaVip: aliyun vpc describe-havips --havip-id ID For IpAddress: aliyun vpc describe-vpcs --vpc-id ID Note: If resource not found, STOP before Phase 2.

Step 1.7.3: Summary of validation results

Show user a summary:

✅ Pre-allocation validation passed!
Region: {REGION} | Target: {INSTANCE_TYPE} {RESOURCE_ID} | Status: {STATUS}
EIP Config: {BANDWIDTH}Mbps | {ISP} | {INTERNET_CHARGE_TYPE} [Name: {EIP_NAME}]
Proceeding to allocate EIP...

Phase 2: Allocate EIP (Only for New EIP)

This phase is ONLY executed when USE_EXISTING_EIP = false (creating new EIP). If using existing EIP (USE_EXISTING_EIP = true), skip directly to Phase 3 (bind).

Step 2.1: Allocate EIP with user-confirmed parameters

Generate ClientToken for idempotency (prevents duplicate EIP on retry):

CLIENT_TOKEN=$(uuidgen | tr -d '-' | head -c 32)

Build command dynamically:

aliyun vpc allocate-eip-address \
  --biz-region-id {REGION} \
  --bandwidth {BANDWIDTH} \
  --isp {ISP} \
  --internet-charge-type {INTERNET_CHARGE_TYPE} \
  --client-token $CLIENT_TOKEN \
  [--name "{EIP_NAME}"] \
  --user-agent AlibabaCloud-Agent-Skills/alibabacloud-network-eip-associate

Notes:

• --client-token ensures idempotency: same token within 10min returns same EIP
• Only include --name parameter if EIP_NAME is not empty
• Default to --internet-charge-type PayByTraffic (pay-by-traffic) Extract from response:
• AllocationId: EIP instance ID (e.g., eip-bp1xxx)
• EipAddress: Public IP address (e.g., 47.1.2.3) Save to tracking variable:

CREATED_EIPS.append(AllocationId)

Step 2.2: Handle allocation errors (Fail Fast)

If QuotaExceeded.Eip: STOP. List current EIPs if user wants. Other errors (InvalidParameter, InsufficientBalance): STOP immediately.

Step 2.3: Wait for EIP to become Available

Query EIP status with maximum 30 retries (5s interval = 150s total):

for i in {1..30}; do
  aliyun vpc describe-eip-addresses \
    --biz-region-id {REGION} \
    --allocation-id {ALLOCATION_ID} \
    --user-agent AlibabaCloud-Agent-Skills/alibabacloud-network-eip-associate

  # Check if Status = "Available"
  # If Available: break
  # If not: sleep 5 seconds and retry
done

If status is NOT "Available" after 30 retries:

❌ ERROR: EIP {ALLOCATION_ID} not Available after 150s. Status: {CURRENT_STATUS}. Cleaning up...

Trigger cleanup (go to Phase 5: Cleanup on Failure).

Step 2.4: Show allocated EIP information

✅ EIP allocated successfully!
EIP: {EipAddress} | ID: {AllocationId} | {BANDWIDTH}Mbps | {ISP} | {INTERNET_CHARGE_TYPE}
Proceeding to bind to {RESOURCE_TYPE} {RESOURCE_ID}...

Phase 3: Bind EIP to Target Resource

Step 3.1: Build AssociateEipAddress command

Base command structure:

aliyun vpc associate-eip-address \
  --biz-region-id {REGION} \
  --allocation-id {ALLOCATION_ID} \
  --instance-id {RESOURCE_ID} \
  --instance-type {INSTANCE_TYPE} \
  [--private-ip-address {PRIVATE_IP}] \
  [--vpc-id {VPC_ID}] \
  --user-agent AlibabaCloud-Agent-Skills/alibabacloud-network-eip-associate

Instance Type Mapping:

• If INSTANCE_TYPE = NetworkInterface and PRIVATE_IP is empty: ERROR - PrivateIpAddress REQUIRED. STOP.
• If INSTANCE_TYPE = IpAddress and VPC_ID is empty: ERROR - VpcId REQUIRED. STOP.

Step 3.2: Execute binding

Execute the constructed command. Success response: Extract RequestId and proceed to verification.

Step 3.3: Handle binding errors (Fail Fast)

Common binding errors:

❌ ERROR: Failed to bind EIP to {RESOURCE_TYPE} {RESOURCE_ID}
Error: {ERROR_CODE} - {ERROR_MESSAGE}
Possible causes: Resource not exist, already has EIP bound, wrong state, invalid parameters.
Cleaning up...

Trigger cleanup (Phase 5). Do NOT retry indefinitely. Fail fast and cleanup.

Phase 4: Verify Binding

Step 4.1: Query EIP status to confirm binding

Wait briefly (5 seconds), then query:

aliyun vpc describe-eip-addresses \
  --biz-region-id {REGION} \
  --allocation-id {ALLOCATION_ID} \
  --user-agent AlibabaCloud-Agent-Skills/alibabacloud-network-eip-associate

Expected response:

• Status: InUse
• InstanceType: Matches {INSTANCE_TYPE}
• InstanceId: Matches {RESOURCE_ID} If verification passes:

✅ SUCCESS: EIP binding completed!
EIP: {EipAddress} | ID: {AllocationId} | Bound to: {INSTANCE_TYPE} {RESOURCE_ID} | Region: {REGION} | Status: InUse

Remove from cleanup tracking:

CREATED_EIPS.remove(AllocationId)  # Binding successful, no cleanup needed

If verification fails (Status != InUse or wrong InstanceId):

⚠️ WARNING: Binding command succeeded but verification failed.
Expected: Status=InUse, InstanceId={RESOURCE_ID}
Actual: Status={ACTUAL_STATUS}, InstanceId={ACTUAL_INSTANCE_ID}
Please check EIP status manually in Console.

Do NOT trigger cleanup in this case (binding may be in progress).

Phase 5: Cleanup on Failure

This phase is ONLY executed when an unrecoverable error occurs during Phase 2 or Phase 3. IMPORTANT: Only applies to newly created EIPs (USE_EXISTING_EIP = false). Do NOT release user's existing EIPs.

Step 5.1: Ask user about cleanup

If binding failed and CREATED_EIPS is not empty (newly created EIP in this session): List the newly created EIPs:

aliyun vpc describe-eip-addresses \
  --biz-region-id {REGION} \
  --allocation-id {ALLOCATION_ID} \
  --user-agent AlibabaCloud-Agent-Skills/alibabacloud-network-eip-associate

Show user the information and ask:

❌ ERROR: EIP binding failed. Error: {ERROR_CODE} - {ERROR_MESSAGE}
Newly Created EIP: {EipAddress} | ID: {AllocationId} | {BANDWIDTH}Mbps | {ISP}
⚠️ This EIP was created but binding failed.
Options: A) Keep EIP (bind later) | B) Release EIP (avoid charges)
Your choice (A/B):

Wait for user decision.

Step 5.2: Execute cleanup if user chooses to release

If Option B: Check EIP status, unbind if InUse, then release:

# If InUse: aliyun vpc unassociate-eip-address --allocation-id {ALLOCATION_ID} --instance-id {INSTANCE_ID} --instance-type {INSTANCE_TYPE}
# Release: aliyun vpc release-eip-address --allocation-id {ALLOCATION_ID}

Success: ✅ Released EIP {AllocationId} Fail: ❌ CLEANUP FAILED - Manually release via Console

Step 5.3: If user chooses to keep EIP

If user chooses Option A (keep EIP):

✅ EIP {AllocationId} ({EipAddress}) kept. Bind later with: aliyun vpc associate-eip-address --allocation-id {AllocationId} --instance-id \x3CID> --instance-type \x3CTYPE>

Step 5.4: Final summary

Operation aborted. Binding: Failed | Error: {ERROR_CODE} | EIP: {AllocationId} | Cleanup: [Kept/Released]

Error Recovery Reference

Best Practices

1. Region Must Be Explicit: No default region
2. Pre-check EIP Binding: DescribeEipAddresses before proceeding
3. Pre-check ECS PIP: DescribeInstanceAttribute for ECS
4. PIP vs EIP: Mutually exclusive (PIP fixed, EIP dynamic)
5. User Choice: Existing EIP or new EIP
6. User-Controlled Cleanup: ASK user, never auto-release
7. Only Cleanup New EIPs: Never release pre-existing EIPs
8. Default PayByTraffic: Unless user requests PayByBandwidth. PrePaid (subscription) is NOT supported.
9. 30 Retry Limit: 150s total for status checks
10. Security: Never read/echo AK/SK values

Reference Documentation