Flannel is a CNI plugin that provides VPC-based networking for pod-to-pod communication in ACK clusters.
Overview
Flannel allocates a pod CIDR block independent of the Virtual Private Cloud (VPC) CIDR block and forwards packets via the VPC route table, eliminating tunneling such as VXLAN and improving network efficiency. See Network overview.
Usage notes
Flannel is a stable, open-source CNI plugin that delivers high-performance networking with VPC. See flannel.
Version compatibility
The following table lists the active Flannel version for each Kubernetes version.
| Kubernetes version |
Active Flannel version |
| 1.35 or later |
v0.28.0.6 |
| 1.26 to 1.34 |
v0.15.1.23-33d25c1-aliyun |
| Earlier than 1.26 |
v0.15.1.22-20a397e6-aliyun |
Release notes
March 2026
| Version |
Image address |
Release date |
Changes |
Impact |
| v0.28.0.6 |
registry-cn-hangzhou.ack.aliyuncs.com/acs/flannel:v0.28.0.6 |
March 2, 2026 |
- Upgraded the cni-plugin version to support nftables mode switching.
- Fixed multiple CVE vulnerabilities.
|
Applies to clusters running Kubernetes 1.35 or later. Earlier clusters continue to use v0.15.1.23-33d25c1-aliyun. |
May 2024
| Version |
Image address |
Release date |
Changes |
Impact |
| v0.15.1.23-33d25c1-aliyun |
registry-cn-hangzhou.ack.aliyuncs.com/acs/flannel:v0.15.1.23-33d25c1-aliyun |
May 20, 2024 |
Improved Flannel compatibility on Windows. |
Applies to clusters running Kubernetes 1.26 or later. Earlier clusters continue to use v0.15.1.22-20a397e6-aliyun. |
December 2022
| Version |
Image address |
Release date |
Changes |
Impact |
| v0.15.1.22-20a397e6-aliyun |
registry.cn-hangzhou.aliyuncs.com/acs/flannel:v0.15.1.22-20a397e6-aliyun |
December 6, 2022 |
Changed the DaemonSet update policy from OnDelete to RollingUpdate. YAML changes now apply to all Flannel pods automatically through a rolling update, without deleting and recreating pods. See DaemonSet update strategy. |
After updating to this version, manual YAML changes are automatically applied to all Flannel pods through a rolling update. No pod deletion required. |
October 2022
| Version |
Image address |
Release date |
Changes |
Impact |
| v0.15.1.19-d460293f-aliyun |
registry.cn-hangzhou.aliyuncs.com/acs/flannel:v0.15.1.19-d460293f-aliyun |
October 27, 2022 |
- Added compatibility when the CNIVersion field is missing.
- Fixed the CVE-2021-45079 vulnerability.
|
No impact on workloads. |
September 2022
| Version |
Image address |
Release date |
Changes |
Impact |
| v0.15.1.18-6f371e73-aliyun |
registry.cn-hangzhou.aliyuncs.com/acs/flannel:v0.15.1.18-6f371e73-aliyun |
September 26, 2022 |
Disabled Node Informer by default to improve performance. |
No impact on workloads. |
August 2022
| Version |
Image address |
Release date |
Changes |
Impact |
| v0.15.1.13-941db231-aliyun |
registry.cn-hangzhou.aliyuncs.com/acs/flannel:v0.15.1.13-941db231-aliyun |
August 29, 2022 |
Fixed the CVE-2022-37434 vulnerability. |
No impact on workloads. |
July 2022
| Version |
Image address |
Release date |
Changes |
Impact |
| v0.15.1.11-7e95fe23-aliyun |
registry.cn-hangzhou.aliyuncs.com/acs/flannel:v0.15.1.11-7e95fe23-aliyun |
July 28, 2022 |
Changed the default IP address cache directory to /var/run to prevent IP leaks caused by node restarts. |
No impact on workloads. |
May 2022
| Version |
Image address |
Release date |
Changes |
Impact |
| v0.15.1.8-1634a106-aliyun |
registry.cn-hangzhou.aliyuncs.com/acs/flannel:v0.15.1.8-1634a106-aliyun |
May 10, 2022 |
Fixed the CVE-2022-28391 vulnerability. |
No impact on workloads. |
April 2022
| Version |
Image address |
Release date |
Changes |
Impact |
| v0.15.1.6-a320565c-aliyun |
registry.cn-hangzhou.aliyuncs.com/acs/flannel:v0.15.1.6-a320565c-aliyun |
April 8, 2022 |
Added an init container for Flannel installation. |
No impact on workloads. |
January 2022
| Version |
Image address |
Release date |
Changes |
Impact |
| v0.15.1.5-11d1c700-aliyun |
registry.cn-hangzhou.aliyuncs.com/acs/flannel:v0.15.1.5-11d1c700-aliyun |
January 25, 2022 |
Added support for ARM64 instances. |
No impact on workloads. |
December 2021
| Version |
Image address |
Release date |
Changes |
Impact |
| v0.15.1.4-e02c8f12-aliyun |
registry.cn-hangzhou.aliyuncs.com/acs/flannel:v0.15.1.4-e02c8f12-aliyun |
December 1, 2021 |
|
No impact on workloads. |
May 2021
| Version |
Image address |
Release date |
Changes |
Impact |
| v0.13.0.1-466064b-aliyun |
registry.cn-hangzhou.aliyuncs.com/acs/flannel:v0.13.0.1-466064b-aliyun |
May 24, 2021 |
- Added iptables support for compatibility with CentOS 8 and Alibaba Cloud Linux 3 and later.
- Added proactive checks and automatic correction of IP forwarding configurations.
|
No impact on workloads. |
August 2019
| Version |
Image address |
Release date |
Changes |
Impact |
| v0.11.0.2-g6e46593e-aliyun |
registry.cn-hangzhou.aliyuncs.com/acs/flannel:v0.11.0.2-g6e46593e-aliyun |
August 2, 2019 |
Fixed source IP address loss after Flannel upgrades. |
No impact on workloads. If a container name conflict causes the upgrade to fail, see Troubleshoot component exceptions. |