ok, after I put together everything I managed to find from the official documentation and from other forum examples, here's what I have so far.
For the moment my approach is to stop the traefik 1.7 container and start another one based on 2.0.1 for tests until I have a working environment again.
Dashboard available, and Bazarr service looks ok.
9 Routers, 7 Services and 2 Middlewares. To be noted that only one (bazarr) container is setup for traefik 2.0
No errors across the dashboard, but certificates are not being fetched.
Here's my latest log since the last restart of the container.
time="2019-10-01T14:47:03+03:00" level=info msg="Server stopped",
time="2019-10-01T14:47:03+03:00" level=info msg="Shutting down",
time="2019-10-01T14:47:11+03:00" level=info msg="Configuration loaded from file: /etc/traefik/traefik.yml",
time="2019-10-01T14:47:11+03:00" level=info msg="Traefik version 2.0.1 built on 2019-09-26T16:18:03Z",
time="2019-10-01T14:47:11+03:00" level=debug msg="Static configuration loaded {\"global\":{\"checkNewVersion\":true},\"serversTransport\":{\"insecureSkipVerify\":true,\"maxIdleConnsPerHost\":200},\"entryPoints\":{\"http\":{\"address\":\":80\",\"transport\":{\"lifeCycle\":{\"graceTimeOut\":10000000000},\"respondingTimeouts\":{\"idleTimeout\":180000000000}},\"forwardedHeaders\":{}},\"https\":{\"address\":\":443\",\"transport\":{\"lifeCycle\":{\"graceTimeOut\":10000000000},\"respondingTimeouts\":{\"idleTimeout\":180000000000}},\"forwardedHeaders\":{}},\"traefik\":{\"address\":\":8080\",\"transport\":{\"lifeCycle\":{\"graceTimeOut\":10000000000},\"respondingTimeouts\":{\"idleTimeout\":180000000000}},\"forwardedHeaders\":{}}},\"providers\":{\"providersThrottleDuration\":2000000000,\"docker\":{\"watch\":true,\"endpoint\":\"unix:///var/run/docker.sock\",\"defaultRule\":\"Host(`{{ normalize .Name }}`)\",\"swarmModeRefreshSeconds\":15000000000},\"file\":{\"watch\":true,\"filename\":\"/etc/traefik/rules.toml\"}},\"api\":{\"insecure\":true,\"dashboard\":true},\"log\":{\"level\":\"DEBUG\",\"format\":\"common\"},\"certificatesResolvers\":{\"default\":{\"acme\":{\"email\":\"EMAIL@gmail.com\",\"caServer\":\"https://acme-v02.api.letsencrypt.org/directory\",\"storage\":\"/acme.json\",\"keyType\":\"RSA4096\",\"dnsChallenge\":{\"provider\":\"cloudflare\",\"delayBeforeCheck\":120000000000,\"resolvers\":[\"1.1.1.1:53\"]}}}}}",
time="2019-10-01T14:47:11+03:00" level=info msg="\nStats collection is disabled.\nHelp us improve Traefik by turning this feature on :)\nMore details on: https://docs.traefik.io/v2.0/contributing/data-collection/\n",
time="2019-10-01T14:47:11+03:00" level=debug msg="No default certificate, generating one",
time="2019-10-01T14:47:11+03:00" level=info msg="Starting provider aggregator.ProviderAggregator {}",
time="2019-10-01T14:47:11+03:00" level=debug msg="Start TCP Server" entryPointName=https,
time="2019-10-01T14:47:11+03:00" level=debug msg="Start TCP Server" entryPointName=traefik,
time="2019-10-01T14:47:11+03:00" level=debug msg="Start TCP Server" entryPointName=http,
time="2019-10-01T14:47:11+03:00" level=info msg="Starting provider *file.Provider {\"watch\":true,\"filename\":\"/etc/traefik/rules.toml\"}",
time="2019-10-01T14:47:11+03:00" level=error msg="Cannot start the provider *file.Provider: error reading configuration file: /etc/traefik/rules.toml - open /etc/traefik/rules.toml: no such file or directory",
time="2019-10-01T14:47:11+03:00" level=info msg="Starting provider *acme.Provider {\"email\":\"EMAIL@gmail.com\",\"caServer\":\"https://acme-v02.api.letsencrypt.org/directory\",\"storage\":\"/acme.json\",\"keyType\":\"RSA4096\",\"dnsChallenge\":{\"provider\":\"cloudflare\",\"delayBeforeCheck\":120000000000,\"resolvers\":[\"1.1.1.1:53\"]},\"ResolverName\":\"default\",\"store\":{},\"ChallengeStore\":{}}",
time="2019-10-01T14:47:11+03:00" level=info msg="Testing certificate renew..." providerName=default.acme,
time="2019-10-01T14:47:11+03:00" level=info msg="Starting provider *docker.Provider {\"watch\":true,\"endpoint\":\"unix:///var/run/docker.sock\",\"defaultRule\":\"Host(`{{ normalize .Name }}`)\",\"swarmModeRefreshSeconds\":15000000000}",
time="2019-10-01T14:47:11+03:00" level=debug msg="Configuration received from provider default.acme: {\"http\":{},\"tls\":{}}" providerName=default.acme,
time="2019-10-01T14:47:11+03:00" level=debug msg="No default certificate, generating one",
time="2019-10-01T14:47:11+03:00" level=debug msg="Provider connection established with docker 19.03.2 (API 1.40)" providerName=docker,
time="2019-10-01T14:47:11+03:00" level=debug msg="Filtering disabled container" providerName=docker container=kibana-media-server-c1316fbc05f3a7eb527d270d1f1a037f84d0b8fff256f0abd5d5392bd8668291,
time="2019-10-01T14:47:11+03:00" level=debug msg="Filtering disabled container" providerName=docker container=filebeat-media-server-f80e988ab2b068b18cdc6fb193817361377435241652be1cf18f20b37346bae5,
time="2019-10-01T14:47:11+03:00" level=debug msg="Filtering disabled container" providerName=docker container=elasticsearch-media-server-48620b88fa282f6d4471f3ae2a36155d0e3c12d78dda63e59b49a1218e6111a8,
time="2019-10-01T14:47:11+03:00" level=debug msg="Filtering disabled container" container=ouroboros-media-server-2c373d7a804d3b62c02c16fe99dda574996cbe0f7bb0c004a245b8a1c41166df providerName=docker,
time="2019-10-01T14:47:11+03:00" level=debug msg="Filtering disabled container" container=chronograf-media-server-42f5ff510c4cae99e65defc4f42a9ce0c04466cda021117f9879cf3376f6504e providerName=docker,
time="2019-10-01T14:47:11+03:00" level=debug msg="Filtering disabled container" providerName=docker container=influxdb-telegraf-media-server-5ea37b993a0dfa03a961971d7ca28b8cd9cc745642de30e541963e2b03259c93,
time="2019-10-01T14:47:11+03:00" level=debug msg="Filtering disabled container" providerName=docker container=portainer-media-server-c5d350f8f78bd181729c91f52e3a9cbcfca18b4072c807a321307a5aca415a60,
time="2019-10-01T14:47:11+03:00" level=debug msg="Filtering disabled container" providerName=docker container=logarr-media-server-c7cf89bea2d8bc5b4ffbfc25ab4513b9e5ffb714ecb18f46b793a7bdf93fd7f5,
time="2019-10-01T14:47:11+03:00" level=debug msg="Filtering disabled container" providerName=docker container=cloudflare-ddns-media-server-c885127c8daf936bcec87b253a9aa404500bf662ff7c50f7e6fc63f898ae55c4,
time="2019-10-01T14:47:11+03:00" level=debug msg="Filtering disabled container" providerName=docker container=piholeinflux-media-server-462d6822c39e3da20a725b24ad3c60ed7a2a61d37a996f9bf33431aeceada7b9,
time="2019-10-01T14:47:11+03:00" level=debug msg="Configuration received from provider docker: {\"http\":{\"routers\":{\"bazarr_http\":{\"entryPoints\":[\"http\"],\"middlewares\":[\"redirect-https-bazarr\"],\"service\":\"bazarr\",\"rule\":\"Host(`bazarr.DOMAIN.com`)\"},\"bazarr_https\":{\"entryPoints\":[\"https\"],\"service\":\"bazarr\",\"rule\":\"Host(`bazarr.DOMAIN.com`)\",\"tls\":{\"certResolver\":\"letsencrypt\"}},\"grafana-media-server\":{\"service\":\"grafana-media-server\",\"rule\":\"Host(`grafana-media-server`)\"},\"heimdall-media-server\":{\"service\":\"heimdall-media-server\",\"rule\":\"Host(`heimdall-media-server`)\"},\"http_traefik\":{\"entryPoints\":[\"http\"],\"middlewares\":[\"https_redirect\"],\"service\":\"traefik-2-0-1-media-server\",\"rule\":\"Host(`traefik.localhost`)\"},\"ombi-media-server\":{\"service\":\"ombi-media-server\",\"rule\":\"Host(`ombi-media-server`)\"},\"organizr-media-server\":{\"service\":\"organizr-media-server\",\"rule\":\"Host(`organizr-media-server`)\"},\"tautulli-media-server\":{\"service\":\"tautulli-media-server\",\"rule\":\"Host(`tautulli-media-server`)\"},\"traefik_https\":{\"entryPoints\":[\"https\"],\"service\":\"api@internal\",\"rule\":\"Host(`traefik.localhost`)\",\"tls\":{\"certResolver\":\"letsencrypt\"}}},\"middlewares\":{\"https_redirect\":{\"redirectScheme\":{\"scheme\":\"https\",\"permanent\":true}},\"redirect-https-bazarr\":{\"redirectScheme\":{\"scheme\":\"https\"}}},\"services\":{\"bazarr\":{\"loadBalancer\":{\"servers\":[{\"url\":\"http://172.18.0.7:6767\"}],\"passHostHeader\":true}},\"grafana-media-server\":{\"loadBalancer\":{\"servers\":[{\"url\":\"http://172.18.0.2:3000\"}],\"passHostHeader\":true}},\"heimdall-media-server\":{\"loadBalancer\":{\"servers\":[{\"url\":\"http://172.18.0.15:80\"}],\"passHostHeader\":true}},\"ombi-media-server\":{\"loadBalancer\":{\"servers\":[{\"url\":\"http://172.18.0.4:3579\"}],\"passHostHeader\":true}},\"organizr-media-server\":{\"loadBalancer\":{\"servers\":[{\"url\":\"http://172.18.0.18:80\"}],\"passHostHeader\":true}},\"tautulli-media-server\":{\"loadBalancer\":{\"servers\":[{\"url\":\"http://172.18.0.16:8181\"}],\"passHostHeader\":true}},\"traefik-2-0-1-media-server\":{\"loadBalancer\":{\"servers\":[{\"url\":\"http://172.18.0.8:80\"}],\"passHostHeader\":true}}}},\"tcp\":{}}" providerName=docker,
time="2019-10-01T14:47:12+03:00" level=debug msg="No entryPoint defined for this router, using the default one(s) instead: [https traefik http]" routerName=heimdall-media-server@docker,
time="2019-10-01T14:47:12+03:00" level=debug msg="No entryPoint defined for this router, using the default one(s) instead: [https traefik http]" routerName=organizr-media-server@docker,
time="2019-10-01T14:47:12+03:00" level=debug msg="No entryPoint defined for this router, using the default one(s) instead: [https traefik http]" routerName=grafana-media-server@docker,
time="2019-10-01T14:47:12+03:00" level=debug msg="No entryPoint defined for this router, using the default one(s) instead: [https traefik http]" routerName=ombi-media-server@docker,
time="2019-10-01T14:47:12+03:00" level=debug msg="No entryPoint defined for this router, using the default one(s) instead: [https traefik http]" routerName=tautulli-media-server@docker,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating middleware" routerName=http_traefik@docker serviceName=traefik-2-0-1-media-server entryPointName=http middlewareName=pipelining middlewareType=Pipelining,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating load-balancer" entryPointName=http routerName=http_traefik@docker serviceName=traefik-2-0-1-media-server,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating server 0 http://172.18.0.8:80" entryPointName=http routerName=http_traefik@docker serviceName=traefik-2-0-1-media-server serverName=0,
time="2019-10-01T14:47:12+03:00" level=debug msg="Added outgoing tracing middleware traefik-2-0-1-media-server" entryPointName=http routerName=http_traefik@docker middlewareName=tracing middlewareType=TracingForwarder,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating middleware" entryPointName=http routerName=http_traefik@docker middlewareName=https_redirect@docker middlewareType=RedirectScheme,
time="2019-10-01T14:47:12+03:00" level=debug msg="Setting up redirection to https " middlewareName=https_redirect@docker middlewareType=RedirectScheme entryPointName=http routerName=http_traefik@docker,
time="2019-10-01T14:47:12+03:00" level=debug msg="Adding tracing to middleware" entryPointName=http routerName=http_traefik@docker middlewareName=https_redirect@docker,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating middleware" serviceName=organizr-media-server entryPointName=http middlewareName=pipelining middlewareType=Pipelining routerName=organizr-media-server@docker,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating load-balancer" entryPointName=http routerName=organizr-media-server@docker serviceName=organizr-media-server,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating server 0 http://172.18.0.18:80" routerName=organizr-media-server@docker serviceName=organizr-media-server serverName=0 entryPointName=http,
time="2019-10-01T14:47:12+03:00" level=debug msg="Added outgoing tracing middleware organizr-media-server" entryPointName=http middlewareName=tracing middlewareType=TracingForwarder routerName=organizr-media-server@docker,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating middleware" entryPointName=http middlewareName=pipelining middlewareType=Pipelining routerName=grafana-media-server@docker serviceName=grafana-media-server,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating load-balancer" routerName=grafana-media-server@docker serviceName=grafana-media-server entryPointName=http,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating server 0 http://172.18.0.2:3000" routerName=grafana-media-server@docker serviceName=grafana-media-server entryPointName=http serverName=0,
time="2019-10-01T14:47:12+03:00" level=debug msg="Added outgoing tracing middleware grafana-media-server" entryPointName=http middlewareName=tracing middlewareType=TracingForwarder routerName=grafana-media-server@docker,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating middleware" middlewareType=Pipelining entryPointName=http routerName=ombi-media-server@docker serviceName=ombi-media-server middlewareName=pipelining,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating load-balancer" entryPointName=http routerName=ombi-media-server@docker serviceName=ombi-media-server,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating server 0 http://172.18.0.4:3579" entryPointName=http routerName=ombi-media-server@docker serviceName=ombi-media-server serverName=0,
time="2019-10-01T14:47:12+03:00" level=debug msg="Added outgoing tracing middleware ombi-media-server" entryPointName=http routerName=ombi-media-server@docker middlewareName=tracing middlewareType=TracingForwarder,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating middleware" entryPointName=http routerName=tautulli-media-server@docker middlewareName=pipelining middlewareType=Pipelining serviceName=tautulli-media-server,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating load-balancer" serviceName=tautulli-media-server entryPointName=http routerName=tautulli-media-server@docker,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating server 0 http://172.18.0.16:8181" serverName=0 entryPointName=http routerName=tautulli-media-server@docker serviceName=tautulli-media-server,
time="2019-10-01T14:47:12+03:00" level=debug msg="Added outgoing tracing middleware tautulli-media-server" middlewareName=tracing routerName=tautulli-media-server@docker entryPointName=http middlewareType=TracingForwarder,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating middleware" serviceName=bazarr routerName=bazarr_http@docker entryPointName=http middlewareName=pipelining middlewareType=Pipelining,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating load-balancer" routerName=bazarr_http@docker entryPointName=http serviceName=bazarr,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating server 0 http://172.18.0.7:6767" entryPointName=http serviceName=bazarr serverName=0 routerName=bazarr_http@docker,
time="2019-10-01T14:47:12+03:00" level=debug msg="Added outgoing tracing middleware bazarr" middlewareName=tracing middlewareType=TracingForwarder entryPointName=http routerName=bazarr_http@docker,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating middleware" middlewareType=RedirectScheme entryPointName=http routerName=bazarr_http@docker middlewareName=redirect-https-bazarr@docker,
time="2019-10-01T14:47:12+03:00" level=debug msg="Setting up redirection to https " entryPointName=http routerName=bazarr_http@docker middlewareName=redirect-https-bazarr@docker middlewareType=RedirectScheme,
time="2019-10-01T14:47:12+03:00" level=debug msg="Adding tracing to middleware" routerName=bazarr_http@docker middlewareName=redirect-https-bazarr@docker entryPointName=http,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating middleware" serviceName=heimdall-media-server middlewareName=pipelining middlewareType=Pipelining entryPointName=http routerName=heimdall-media-server@docker,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating load-balancer" entryPointName=http routerName=heimdall-media-server@docker serviceName=heimdall-media-server,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating server 0 http://172.18.0.15:80" serviceName=heimdall-media-server entryPointName=http routerName=heimdall-media-server@docker serverName=0,
time="2019-10-01T14:47:12+03:00" level=debug msg="Added outgoing tracing middleware heimdall-media-server" entryPointName=http routerName=heimdall-media-server@docker middlewareName=tracing middlewareType=TracingForwarder,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating middleware" entryPointName=http middlewareName=traefik-internal-recovery middlewareType=Recovery,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating middleware" entryPointName=https middlewareName=traefik-internal-recovery middlewareType=Recovery,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating middleware" entryPointName=traefik middlewareName=traefik-internal-recovery middlewareType=Recovery,
time="2019-10-01T14:47:12+03:00" level=debug msg="Added outgoing tracing middleware api@internal" middlewareType=TracingForwarder entryPointName=https routerName=traefik_https@docker middlewareName=tracing,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating middleware" serviceName=bazarr entryPointName=https routerName=bazarr_https@docker middlewareName=pipelining middlewareType=Pipelining,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating load-balancer" entryPointName=https routerName=bazarr_https@docker serviceName=bazarr,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating server 0 http://172.18.0.7:6767" entryPointName=https routerName=bazarr_https@docker serviceName=bazarr serverName=0,
time="2019-10-01T14:47:12+03:00" level=debug msg="Added outgoing tracing middleware bazarr" middlewareName=tracing middlewareType=TracingForwarder entryPointName=https routerName=bazarr_https@docker,
time="2019-10-01T14:47:12+03:00" level=debug msg="Creating middleware" entryPointName=https middlewareName=traefik-internal-recovery middlewareType=Recovery,
time="2019-10-01T14:47:12+03:00" level=debug msg="No default certificate, generating one",
time="2019-10-01T14:47:12+03:00" level=error msg="the router traefik_https uses a non-existent resolver: letsencrypt",
time="2019-10-01T14:47:12+03:00" level=error msg="the router bazarr_https uses a non-existent resolver: letsencrypt",
time="2019-10-01T14:49:02+03:00" level=debug msg="Serving default certificate for request: \"bazarr.DOMAIN.com\"",
time="2019-10-01T14:49:02+03:00" level=debug msg="http: TLS handshake error from 172.18.0.1:45524: remote error: tls: unknown certificate",
time="2019-10-01T14:49:02+03:00" level=debug msg="Serving default certificate for request: \"bazarr.DOMAIN.com\"",
time="2019-10-01T14:49:02+03:00" level=debug msg="http: TLS handshake error from 172.18.0.1:45554: remote error: tls: unknown certificate",
time="2019-10-01T14:49:03+03:00" level=debug msg="Serving default certificate for request: \"bazarr.DOMAIN.com\"",
time="2019-10-01T14:49:03+03:00" level=debug msg="http: TLS handshake error from 172.18.0.1:45570: remote error: tls: unknown certificate",
Later Edit: Tried to fine tune the certificate part and try to put everything in a more orderly fashion and now bazarr dropped from the services list and I lost the middleware 