Let’s Encrypt

    You can configure Traefik to use an ACME provider (like Let’s Encrypt) for automatic certificate generation.

    Let’s Encrypt and Rate Limiting

    Note that Let’s Encrypt API has rate limiting.

    Use Let’s Encrypt staging server with the configuration option when experimenting to avoid hitting this limit too fast.

    Traefik requires you to define “Certificate Resolvers” in the static configuration, which are responsible for retrieving certificates from an ACME server.

    Then, each is configured to enable TLS, and is associated to a certificate resolver through the tls.certresolver configuration option.

    Certificates are requested for domain names retrieved from the router’s .

    You can read more about this retrieval mechanism in the following section: ACME Domain Definition.

    Defining a certificates resolver does not result in all routers automatically using it. Each router that is supposed to use the resolver must it.

    Configuration Reference

    There are many available options for ACME. For a quick glance at what’s possible, browse the configuration reference:

    File (TOML)

    File (YAML)

    1. certificatesResolvers:
    2.   myresolver:
    3.     # Enable ACME (Let's Encrypt): automatic SSL.
    4.     acme:
    6.       # Email address used for registration.
    7.       #
    8.       # Required
    9.       #
    10.       email: "test@example.com"
    12.       # File or key used for certificates storage.
    13.       #
    14.       # Required
    15.       #
    16.       storage: "acme.json"
    18.       # CA server to use.
    19.       # Uncomment the line to use Let's Encrypt's staging server,
    20.       # leave commented to go to prod.
    21.       #
    22.       # Optional
    23.       # Default: "https://acme-v02.api.letsencrypt.org/directory"
    24.       #
    25.       # caServer: "https://acme-staging-v02.api.letsencrypt.org/directory"
    27.       # Preferred chain to use.
    28.       #
    29.       # If the CA offers multiple certificate chains, prefer the chain with an issuer matching this Subject Common Name.
    30.       # If no match, the default offered chain will be used.
    31.       #
    32.       # Optional
    33.       # Default: ""
    34.       #
    35.       # preferredChain: 'ISRG Root X1'
    37.       # KeyType to use.
    38.       #
    39.       # Optional
    40.       # Default: "RSA4096"
    41.       #
    42.       # Available values : "EC256", "EC384", "RSA2048", "RSA4096", "RSA8192"
    43.       #
    44.       # keyType: RSA4096
    46.       # Use a TLS-ALPN-01 ACME challenge.
    47.       #
    48.       # Optional (but recommended)
    49.       #
    50.       tlsChallenge:
    52.       # Use a HTTP-01 ACME challenge.
    53.       #
    54.       # Optional
    55.       #
    56.       # httpChallenge:
    58.         # EntryPoint to use for the HTTP-01 challenges.
    59.         #
    60.         # Required
    61.         #
    62.         # entryPoint: web
    64.       # Use a DNS-01 ACME challenge rather than HTTP-01 challenge.
    65.       # Note: mandatory for wildcard certificate generation.
    66.       #
    67.       # Optional
    68.       #
    69.       # dnsChallenge:
    71.         # DNS provider used.
    72.         #
    73.         # Required
    74.         #
    75.         # provider: digitalocean
    77.         # By default, the provider will verify the TXT DNS challenge record before letting ACME verify.
    78.         # If delayBeforeCheck is greater than zero, this check is delayed for the configured duration in seconds.
    79.         # Useful if internal networks block external DNS queries.
    80.         #
    81.         # Optional
    82.         # Default: 0
    83.         #
    84.         # delayBeforeCheck: 0
    86.         # Use following DNS servers to resolve the FQDN authority.
    87.         #
    88.         # Optional
    89.         # Default: empty
    90.         #
    91.         # resolvers
    92.         # - "1.1.1.1:53"
    93.         # - "8.8.8.8:53"
    95.         # Disable the DNS propagation checks before notifying ACME that the DNS challenge is ready.
    96.         #
    97.         # NOT RECOMMENDED:
    98.         # Increase the risk of reaching Let's Encrypt's rate limits.
    99.         #
    100.         # Optional
    101.         # Default: false
    102.         #
    103.         # disablePropagationCheck: true

    CLI

    1. # Enable ACME (Let's Encrypt): automatic SSL.
    3. # Email address used for registration.
    4. #
    5. # Required
    6. #
    7. --certificatesresolvers.myresolver.acme.email=test@example.com
    9. # File or key used for certificates storage.
    10. #
    11. # Required
    12. #
    13. --certificatesresolvers.myresolver.acme.storage=acme.json
    15. # CA server to use.
    16. # Uncomment the line to use Let's Encrypt's staging server,
    17. # leave commented to go to prod.
    18. #
    19. # Optional
    20. # Default: "https://acme-v02.api.letsencrypt.org/directory"
    21. #
    22. --certificatesresolvers.myresolver.acme.caserver=https://acme-staging-v02.api.letsencrypt.org/directory
    24. # Preferred chain to use.
    25. #
    26. # If the CA offers multiple certificate chains, prefer the chain with an issuer matching this Subject Common Name.
    27. # If no match, the default offered chain will be used.
    28. #
    29. # Optional
    30. # Default: ""
    31. #
    32. --certificatesresolvers.myresolver.acme.preferredchain="ISRG Root X1"
    34. # KeyType to use.
    35. #
    36. # Optional
    37. # Default: "RSA4096"
    38. #
    39. # Available values : "EC256", "EC384", "RSA2048", "RSA4096", "RSA8192"
    40. #
    41. --certificatesresolvers.myresolver.acme.keytype=RSA4096
    43. # Use a TLS-ALPN-01 ACME challenge.
    44. #
    45. # Optional (but recommended)
    46. #
    47. --certificatesresolvers.myresolver.acme.tlschallenge=true
    49. # Use a HTTP-01 ACME challenge.
    50. #
    51. # Optional
    52. #
    53. --certificatesresolvers.myresolver.acme.httpchallenge=true
    55. # EntryPoint to use for the HTTP-01 challenges.
    56. #
    57. # Required
    58. #
    59. --certificatesresolvers.myresolver.acme.httpchallenge.entrypoint=web
    61. # Use a DNS-01 ACME challenge rather than HTTP-01 challenge.
    62. # Note: mandatory for wildcard certificate generation.
    63. #
    64. # Optional
    65. #
    66. --certificatesresolvers.myresolver.acme.dnschallenge=true
    68. #
    69. # Required
    70. #
    71. --certificatesresolvers.myresolver.acme.dnschallenge.provider=digitalocean
    73. # By default, the provider will verify the TXT DNS challenge record before letting ACME verify.
    74. # If delayBeforeCheck is greater than zero, this check is delayed for the configured duration in seconds.
    75. # Useful if internal networks block external DNS queries.
    76. #
    77. # Optional
    78. # Default: 0
    79. #
    80. --certificatesresolvers.myresolver.acme.dnschallenge.delaybeforecheck=0
    82. # Use following DNS servers to resolve the FQDN authority.
    83. #
    84. # Optional
    85. # Default: empty
    86. #
    87. --certificatesresolvers.myresolver.acme.dnschallenge.resolvers=1.1.1.1:53,8.8.8.8:53
    89. # Disable the DNS propagation checks before notifying ACME that the DNS challenge is ready.
    90. #
    91. # NOT RECOMMENDED:
    92. # Increase the risk of reaching Let's Encrypt's rate limits.
    93. #
    94. # Optional
    95. # Default: false
    96. #
    97. --certificatesresolvers.myresolver.acme.dnschallenge.disablepropagationcheck=true

    Domain Definition

    Certificate resolvers request certificates for a set of the domain names inferred from routers, with the following logic:

    • If the router has a option set, then the certificate resolver uses the main (and optionally sans) option of tls.domains to know the domain names for this router.

    • If no tls.domains option is set, then the certificate resolver uses the , by checking the Host() matchers. Please note that multiple Host() matchers can be used) for specifying multiple domain names for this router.

    Please note that:

    • When multiple domain names are inferred from a given router, only one certificate is requested with the first domain name as the main domain, and the other domains as .

    • As ACME V2 supports “wildcard domains”, any router can provide a name, as “main” domain or as “SAN” domain.

    Please check the configuration examples below for more details.

    Configuration Examples

    Enabling ACME

    File (TOML)

    1. [entryPoints]
    2.   [entryPoints.web]
    3.     address = ":80"
    5.   [entryPoints.websecure]
    6.     address = ":443"
    8. [certificatesResolvers.myresolver.acme]
    9.   email = "your-email@example.com"
    10.   storage = "acme.json"
    11.   [certificatesResolvers.myresolver.acme.httpChallenge]
    12.     # used during the challenge
    13.     entryPoint = "web"

    File (YAML)

    1. entryPoints:
    2.   web:
    3.     address: ":80"
    5.   websecure:
    6.     address: ":443"
    8. certificatesResolvers:
    9.   myresolver:
    10.     acme:
    11.       email: your-email@example.com
    12.       storage: acme.json
    13.       httpChallenge:
    14.         # used during the challenge
    15.         entryPoint: web

    CLI

    1. --entrypoints.web.address=:80
    2. --entrypoints.websecure.address=:443
    3. # ...
    4. --certificatesresolvers.myresolver.acme.email=your-email@example.com
    5. --certificatesresolvers.myresolver.acme.storage=acme.json
    6. # used during the challenge
    7. --certificatesresolvers.myresolver.acme.httpchallenge.entrypoint=web

    Defining a certificates resolver does not result in all routers automatically using it. Each router that is supposed to use the resolver must reference it.

    Single Domain from Router’s Rule Example

    • A certificate for the domain example.com is requested:

    Docker

    1. ## Dynamic configuration
    2. labels:
    3.   - traefik.http.routers.blog.rule=Host(`example.com`) && Path(`/blog`)
    4.   - traefik.http.routers.blog.tls=true
    5.   - traefik.http.routers.blog.tls.certresolver=myresolver

    Docker (Swarm)

    1. ## Dynamic configuration
    2. deploy:
    3.   labels:
    4.     - traefik.http.routers.blog.rule=Host(`example.com`) && Path(`/blog`)
    5.     - traefik.http.routers.blog.tls=true
    6.     - traefik.http.routers.blog.tls.certresolver=myresolver
    7.     - traefik.http.services.blog-svc.loadbalancer.server.port=8080"

    Kubernetes

    1. apiVersion: traefik.containo.us/v1alpha1
    2. kind: IngressRoute
    3. metadata:
    4.   name: blogtls
    5. spec:
    6.   entryPoints:
    7.     - websecure
    8.   routes:
    9.   - match: Host(`example.com`) && Path(`/blog`)
    10.     kind: Rule
    11.     services:
    12.     - name: blog
    13.       port: 8080
    14.   tls:
    15.     certResolver: myresolver

    Marathon

    1. labels: {
    2.   "traefik.http.routers.blog.rule": "Host(`example.com`) && Path(`/blog`)",
    3.   "traefik.http.routers.blog.tls": "true",
    4.   "traefik.http.routers.blog.tls.certresolver": "myresolver",
    6. }

    Rancher

    1. ## Dynamic configuration
    2. labels:
    3.   - traefik.http.routers.blog.rule=Host(`example.com`) && Path(`/blog`)
    4.   - traefik.http.routers.blog.tls=true
    5.   - traefik.http.routers.blog.tls.certresolver=myresolver

    File (TOML)

    1. ## Dynamic configuration
    2. [http.routers]
    3.   [http.routers.blog]
    4.   rule = "Host(`example.com`) && Path(`/blog`)"
    5.   [http.routers.blog.tls]
    6.     certResolver = "myresolver"

    File (YAML)

    1. ## Dynamic configuration
    2. http:
    3.   routers:
    4.     blog:
    5.       rule: "Host(`example.com`) && Path(`/blog`)"
    6.       tls:
    7.         certResolver: myresolver

    Multiple Domains from Router’s Rule Example

    • A certificate for the domains example.com (main) and blog.example.org is requested:

    Docker

    1. ## Dynamic configuration
    2. labels:
    3.   - traefik.http.routers.blog.rule=(Host(`example.com`) && Path(`/blog`)) || Host(`blog.example.org`)
    4.   - traefik.http.routers.blog.tls=true
    5.   - traefik.http.routers.blog.tls.certresolver=myresolver

    Docker (Swarm)

    1. ## Dynamic configuration
    2. deploy:
    3.   labels:
    4.     - traefik.http.routers.blog.rule=(Host(`example.com`) && Path(`/blog`)) || Host(`blog.example.org`)
    5.     - traefik.http.routers.blog.tls=true
    6.     - traefik.http.routers.blog.tls.certresolver=myresolver
    7.     - traefik.http.services.blog-svc.loadbalancer.server.port=8080"

    Kubernetes

    1. apiVersion: traefik.containo.us/v1alpha1
    2. kind: IngressRoute
    3. metadata:
    4.   name: blogtls
    5. spec:
    6.   entryPoints:
    7.     - websecure
    8.   routes:
    9.   - match: (Host(`example.com`) && Path(`/blog`)) || Host(`blog.example.org`)
    10.     kind: Rule
    11.     services:
    12.     - name: blog
    13.       port: 8080
    14.   tls:
    15.     certResolver: myresolver

    Marathon

    1. labels: {
    2.   "traefik.http.routers.blog.rule": "(Host(`example.com`) && Path(`/blog`)) || Host(`blog.example.org`)",
    3.   "traefik.http.routers.blog.tls": "true",
    4.   "traefik.http.routers.blog.tls.certresolver": "myresolver",
    5.   "traefik.http.services.blog-svc.loadbalancer.server.port": "8080"
    6. }

    Rancher

    1. ## Dynamic configuration
    2. labels:
    3.   - traefik.http.routers.blog.rule=(Host(`example.com`) && Path(`/blog`)) || Host(`blog.example.org`)
    4.   - traefik.http.routers.blog.tls=true
    5.   - traefik.http.routers.blog.tls.certresolver=myresolver

    File (YAML)

    1. ## Dynamic configuration
    2. http:
    3.   routers:
    4.     blog:
    5.       rule: "(Host(`example.com`) && Path(`/blog`)) || Host(`blog.example.org`)"
    6.       tls:
    7.         certResolver: myresolver

    Multiple Domains from Router’s tls.domain Example

    • A certificate for the domains example.com (main) and *.example.org (SAN) is requested:

    Docker

    1. ## Dynamic configuration
    2. labels:
    3.   - traefik.http.routers.blog.rule=Host(`example.com`) && Path(`/blog`)
    4.   - traefik.http.routers.blog.tls=true
    5.   - traefik.http.routers.blog.tls.certresolver=myresolver
    6.   - traefik.http.routers.blog.tls.domains[0].main=example.org
    7.   - traefik.http.routers.blog.tls.domains[0].sans=*.example.org

    Docker (Swarm)

    1. ## Dynamic configuration
    2. deploy:
    3.   labels:
    4.     - traefik.http.routers.blog.rule=Host(`example.com`) && Path(`/blog`)
    5.     - traefik.http.services.blog-svc.loadbalancer.server.port=8080"
    6.     - traefik.http.routers.blog.tls=true
    7.     - traefik.http.routers.blog.tls.certresolver=myresolver
    8.     - traefik.http.routers.blog.tls.domains[0].main=example.org
    9.     - traefik.http.routers.blog.tls.domains[0].sans=*.example.org

    Kubernetes

    1. apiVersion: traefik.containo.us/v1alpha1
    2. kind: IngressRoute
    3. metadata:
    4.   name: blogtls
    5. spec:
    6.     - websecure
    7.   routes:
    8.   - match: Host(`example.com`) && Path(`/blog`)
    9.     kind: Rule
    10.     services:
    11.     - name: blog
    12.       port: 8080
    13.   tls:
    14.     certResolver: myresolver
    15.     domains:
    16.     - main: example.org
    17.       sans:
    18.       - '*.example.org'

    Marathon

    1. labels: {
    2.   "traefik.http.routers.blog.rule": "Host(`example.com`) && Path(`/blog`)",
    3.   "traefik.http.routers.blog.tls": "true",
    4.   "traefik.http.routers.blog.tls.certresolver": "myresolver",
    5.   "traefik.http.routers.blog.tls.domains[0].main": "example.com",
    6.   "traefik.http.routers.blog.tls.domains[0].sans": "*.example.com",
    7.   "traefik.http.services.blog-svc.loadbalancer.server.port": "8080"
    8. }

    Rancher

    1. ## Dynamic configuration
    2. labels:
    3.   - traefik.http.routers.blog.rule=Host(`example.com`) && Path(`/blog`)
    4.   - traefik.http.routers.blog.tls=true
    5.   - traefik.http.routers.blog.tls.certresolver=myresolver
    6.   - traefik.http.routers.blog.tls.domains[0].main=example.org
    7.   - traefik.http.routers.blog.tls.domains[0].sans=*.example.org

    File (TOML)

    1. ## Dynamic configuration
    2. [http.routers]
    3.   [http.routers.blog]
    4.     rule = "Host(`example.com`) && Path(`/blog`)"
    5.     [http.routers.blog.tls]
    6.       certResolver = "myresolver" # From static configuration
    7.       [[http.routers.blog.tls.domains]]
    8.         main = "example.org"
    9.         sans = ["*.example.org"]

    File (YAML)

    1. ## Dynamic configuration
    2. http:
    3.   routers:
    4.     blog:
    5.       rule: "Host(`example.com`) && Path(`/blog`)"
    6.       tls:
    7.         certResolver: myresolver
    8.         domains:
    9.           - main: "example.org"
    10.             sans:
    11.               - "*.example.org"

    Traefik automatically tracks the expiry date of ACME certificates it generates.

    If there are less than 30 days remaining before the certificate expires, Traefik will attempt to renew it automatically.

    Certificates that are no longer used may still be renewed, as Traefik does not currently check if the certificate is being used before renewing.

    Using LetsEncrypt with Kubernetes

    When using LetsEncrypt with kubernetes, there are some known caveats with both the ingress and providers.

    If you intend to run multiple instances of Traefik with LetsEncrypt, please ensure you read the sections on those provider pages.

    The Different ACME Challenges

    Defining a certificates resolver does not result in all routers automatically using it. Each router that is supposed to use the resolver must it.

    Use the TLS-ALPN-01 challenge to generate and renew ACME certificates by provisioning a TLS certificate.

    As described on the Let’s Encrypt community forum, when using the TLS-ALPN-01 challenge, Traefik must be reachable by Let’s Encrypt through port 443.

    Configuring the tlsChallenge

    File (TOML)

    1. [certificatesResolvers.myresolver.acme]
    2.   # ...
    3.   [certificatesResolvers.myresolver.acme.tlsChallenge]

    File (YAML)

    1. certificatesResolvers:
    2.   myresolver:
    3.     acme:
    4.       # ...
    5.       tlsChallenge: {}

    CLI

    1. # ...
    2. --certificatesresolvers.myresolver.acme.tlschallenge=true

    httpChallenge

    Use the HTTP-01 challenge to generate and renew ACME certificates by provisioning an HTTP resource under a well-known URI.

    As described on the Let’s Encrypt community forum, when using the HTTP-01 challenge, certificatesresolvers.myresolver.acme.httpchallenge.entrypoint must be reachable by Let’s Encrypt through port 80.

    Using an EntryPoint Called web for the httpChallenge

    File (TOML)

    1. [entryPoints]
    2.   [entryPoints.web]
    3.     address = ":80"
    5.   [entryPoints.websecure]
    6.     address = ":443"
    8. [certificatesResolvers.myresolver.acme]
    9.   # ...
    10.   [certificatesResolvers.myresolver.acme.httpChallenge]
    11.     entryPoint = "web"

    File (YAML)

    1. entryPoints:
    2.   web:
    3.     address: ":80"
    5.   websecure:
    6.     address: ":443"
    8. certificatesResolvers:
    9.   myresolver:
    10.     acme:
    11.       # ...
    12.       httpChallenge:
    13.         entryPoint: web

    CLI

    1. --entrypoints.web.address=:80
    2. --entrypoints.websecure.address=:443
    3. # ...
    4. --certificatesresolvers.myresolver.acme.httpchallenge.entrypoint=web

    Redirection is fully compatible with the HTTP-01 challenge.

    Use the DNS-01 challenge to generate and renew ACME certificates by provisioning a DNS record.

    Configuring a dnsChallenge with the DigitalOcean Provider

    File (TOML)

    1. [certificatesResolvers.myresolver.acme]
    2.   # ...
    3.   [certificatesResolvers.myresolver.acme.dnsChallenge]
    4.     provider = "digitalocean"
    5.     delayBeforeCheck = 0
    6. # ...

    File (YAML)

    1. certificatesResolvers:
    2.   myresolver:
    3.     acme:
    4.       # ...
    5.       dnsChallenge:
    6.         provider: digitalocean
    7.         delayBeforeCheck: 0
    8.     # ...

    CLI

    1. # ...
    2. --certificatesresolvers.myresolver.acme.dnschallenge.provider=digitalocean
    3. --certificatesresolvers.myresolver.acme.dnschallenge.delaybeforecheck=0
    4. # ...

    Important

    A provider is mandatory.

    providers

    Here is a list of supported providers, that can automate the DNS verification, along with the required environment variables and their wildcard & root domain support. Do not hesitate to complete it.

    Many lego environment variables can be overridden by their respective _FILE counterpart, which should have a filepath to a file that contains the secret as its value. For example, CF_API_EMAIL_FILE=/run/secrets/traefik_cf-api-email could be used to provide a Cloudflare API email address as a Docker secret named traefik_cf-api-email.

    For complete details, refer to your provider’s Additional configuration link.

    delayBeforeCheck

    By default, the provider verifies the TXT record before letting ACME verify. You can delay this operation by specifying a delay (in seconds) with delayBeforeCheck (value must be greater than zero). This option is useful when internal networks block external DNS queries.

    resolvers

    File (TOML)

    File (YAML)

    1. certificatesResolvers:
    2.   myresolver:
    3.     acme:
    4.       # ...
    5.       dnsChallenge:
    6.         # ...
    7.         resolvers:
    8.           - "1.1.1.1:53"
    9.           - "8.8.8.8:53"

    CLI

    1. # ...
    2. --certificatesresolvers.myresolver.acme.dnschallenge.resolvers=1.1.1.1:53,8.8.8.8:53

    Wildcard Domains

    supports wildcard certificates. As described in Let’s Encrypt’s post wildcard certificates can only be generated through a .

    • kid: Key identifier from External CA
    • hmacEncoded: HMAC key from External CA, should be in Base64 URL Encoding without padding format

    File (TOML)

    1. [certificatesResolvers.myresolver.acme]
    2.   # ...
    3.   [certificatesResolvers.myresolver.acme.eab]
    4.     kid = "abc-keyID-xyz"
    5.     hmacEncoded = "abc-hmac-xyz"

    File (YAML)

    1. certificatesResolvers:
    2.   myresolver:
    3.     acme:
    4.       # ...
    5.       eab:
    6.         kid: abc-keyID-xyz
    7.         hmacEncoded: abc-hmac-xyz

    CLI

    1. # ...
    2. --certificatesresolvers.myresolver.acme.eab.kid=abc-keyID-xyz
    3. --certificatesresolvers.myresolver.acme.eab.hmacencoded=abc-hmac-xyz

    More Configuration

    caServer

    Required, Default=”https://acme-v02.api.letsencrypt.org/directory“

    The CA server to use:

    Using the Let’s Encrypt staging server

    File (TOML)

    1. [certificatesResolvers.myresolver.acme]
    2.   # ...
    3.   caServer = "https://acme-staging-v02.api.letsencrypt.org/directory"
    4.   # ...

    File (YAML)

    1. certificatesResolvers:
    2.   myresolver:
    3.     acme:
    4.       # ...
    5.       caServer: https://acme-staging-v02.api.letsencrypt.org/directory
    6.       # ...

    CLI

    1. # ...
    2. --certificatesresolvers.myresolver.acme.caserver=https://acme-staging-v02.api.letsencrypt.org/directory
    3. # ...

    Required, Default=”acme.json”

    The storage option sets the location where your ACME certificates are saved to.

    File (TOML)

    1. [certificatesResolvers.myresolver.acme]
    2.   # ...
    3.   storage = "acme.json"
    4.   # ...

    File (YAML)

    1. certificatesResolvers:
    2.   myresolver:
    3.     acme:
    4.       # ...
    5.       storage: acme.json
    6.       # ...

    CLI

    1. # ...
    2. --certificatesresolvers.myresolver.acme.storage=acme.json
    3. # ...

    ACME certificates are stored in a JSON file that needs to have a 600 file mode.

    In Docker you can mount either the JSON file, or the folder containing it:

    1. docker run -v "/my/host/acme.json:/acme.json" traefik
    1. docker run -v "/my/host/acme:/etc/traefik/acme" traefik

    Warning

    For concurrency reasons, this file cannot be shared across multiple instances of Traefik.

    preferredChain

    Optional, Default=””

    Preferred chain to use.

    If the CA offers multiple certificate chains, prefer the chain with an issuer matching this Subject Common Name. If no match, the default offered chain will be used.

    File (TOML)

    1. [certificatesResolvers.myresolver.acme]
    2.   # ...
    3.   preferredChain = "ISRG Root X1"
    4.   # ...

    File (YAML)

    1. certificatesResolvers:
    2.   myresolver:
    3.     acme:
    4.       # ...
    5.       preferredChain: 'ISRG Root X1'
    6.       # ...

    CLI

    1. # ...
    2. --certificatesresolvers.myresolver.acme.preferredChain="ISRG Root X1"
    3. # ...

    Optional, Default=”RSA4096”

    KeyType used for generating certificate private key. Allow value ‘EC256’, ‘EC384’, ‘RSA2048’, ‘RSA4096’, ‘RSA8192’.

    File (TOML)

    1. [certificatesResolvers.myresolver.acme]
    2.   # ...
    3.   keyType = "RSA4096"
    4.   # ...

    File (YAML)

    CLI

    1. # ...
    2. --certificatesresolvers.myresolver.acme.keyType="RSA4096"
    3. # ...

    Fallback

    If Let’s Encrypt is not reachable, the following certificates will apply:

    1. Previously generated ACME certificates (before downtime)
    2. Expired ACME certificates
    3. Provided certificates

    Important

    For new (sub)domains which need Let’s Encrypt authentication, the default Traefik certificate will be used until Traefik is restarted.

    1. more information about the HTTP message format can be found ↩

    2. ↩

    3. ↩

    4. docker stack remark: there is no way to support terminal attached to container when deploying with docker stack, so you might need to run container with docker run -it to generate certificates using manual provider.