Add option to run beacon node in follow mode to EL

[g11tech]

Motivation
We in our test/dev setups want to connect multiple beacon nodes to same EL, the only complication for this is multiple EL requesting head change to the EL causing unknown EL head transitions and issues.

This PR enables to run beacon node in "follow" mode to an EL, which will be driven by only one beacon node in the normal way.
Assuming the EL and its driving beacon node are synced well, this should work out well for other bns as well as they will also be able to follow heads as well as propose when its time for their validators.

This is achieved by adding a flag which can be turned on in the follow nodes disableImportExecutionFcU which will turn off giving head fcU to the EL.

[github-actions]

Performance Report

✔️ no performance regression detected

Full benchmark results

Benchmark suite	Current: ebdc06e	Previous: 1901f97	Ratio
getPubkeys - index2pubkey - req 1000 vs - 250000 vc	3.1829 ms/op	2.9851 ms/op	1.07
getPubkeys - validatorsArr - req 1000 vs - 250000 vc	99.393 us/op	85.457 us/op	1.16
BLS verify - blst-native	2.4622 ms/op	2.2471 ms/op	1.10
BLS verifyMultipleSignatures 3 - blst-native	4.8567 ms/op	4.7621 ms/op	1.02
BLS verifyMultipleSignatures 8 - blst-native	10.544 ms/op	10.539 ms/op	1.00
BLS verifyMultipleSignatures 32 - blst-native	37.583 ms/op	38.958 ms/op	0.96
BLS aggregatePubkeys 32 - blst-native	50.431 us/op	50.409 us/op	1.00
BLS aggregatePubkeys 128 - blst-native	198.90 us/op	204.47 us/op	0.97
getAttestationsForBlock	210.55 ms/op	216.66 ms/op	0.97
isKnown best case - 1 super set check	536.00 ns/op	544.00 ns/op	0.99
isKnown normal case - 2 super set checks	546.00 ns/op	535.00 ns/op	1.02
isKnown worse case - 16 super set checks	531.00 ns/op	531.00 ns/op	1.00
CheckpointStateCache - add get delete	11.682 us/op	11.880 us/op	0.98
validate gossip signedAggregateAndProof - struct	5.4642 ms/op	5.6114 ms/op	0.97
validate gossip attestation - struct	2.5730 ms/op	2.6225 ms/op	0.98
altair verifyImport mainnet_s3766816:31	11.086 s/op	10.689 s/op	1.04
pickEth1Vote - no votes	2.6499 ms/op	2.6007 ms/op	1.02
pickEth1Vote - max votes	31.618 ms/op	28.377 ms/op	1.11
pickEth1Vote - Eth1Data hashTreeRoot value x2048	15.110 ms/op	14.698 ms/op	1.03
pickEth1Vote - Eth1Data hashTreeRoot tree x2048	27.613 ms/op	25.593 ms/op	1.08
pickEth1Vote - Eth1Data fastSerialize value x2048	1.9507 ms/op	1.9212 ms/op	1.02
pickEth1Vote - Eth1Data fastSerialize tree x2048	21.571 ms/op	21.824 ms/op	0.99
bytes32 toHexString	1.4930 us/op	1.4810 us/op	1.01
bytes32 Buffer.toString(hex)	913.00 ns/op	905.00 ns/op	1.01
bytes32 Buffer.toString(hex) from Uint8Array	1.2190 us/op	1.1710 us/op	1.04
bytes32 Buffer.toString(hex) + 0x	920.00 ns/op	852.00 ns/op	1.08
Object access 1 prop	0.50200 ns/op	0.48400 ns/op	1.04
Map access 1 prop	0.36300 ns/op	0.34800 ns/op	1.04
Object get x1000	17.501 ns/op	16.514 ns/op	1.06
Map get x1000	1.2290 ns/op	0.98700 ns/op	1.25
Object set x1000	137.44 ns/op	133.50 ns/op	1.03
Map set x1000	93.188 ns/op	89.261 ns/op	1.04
Return object 10000 times	0.43690 ns/op	0.42410 ns/op	1.03
Throw Error 10000 times	7.3517 us/op	7.0176 us/op	1.05
enrSubnets - fastDeserialize 64 bits	3.7410 us/op	3.8100 us/op	0.98
enrSubnets - ssz BitVector 64 bits	997.00 ns/op	924.00 ns/op	1.08
enrSubnets - fastDeserialize 4 bits	520.00 ns/op	557.00 ns/op	0.93
enrSubnets - ssz BitVector 4 bits	937.00 ns/op	1.0060 us/op	0.93
prioritizePeers score -10:0 att 32-0.1 sync 2-0	128.86 us/op	129.72 us/op	0.99
prioritizePeers score 0:0 att 32-0.25 sync 2-0.25	161.59 us/op	173.83 us/op	0.93
prioritizePeers score 0:0 att 32-0.5 sync 2-0.5	302.98 us/op	329.04 us/op	0.92
prioritizePeers score 0:0 att 64-0.75 sync 4-0.75	694.93 us/op	561.37 us/op	1.24
prioritizePeers score 0:0 att 64-1 sync 4-1	579.01 us/op	564.49 us/op	1.03
RateTracker 1000000 limit, 1 obj count per request	231.22 ns/op	221.40 ns/op	1.04
RateTracker 1000000 limit, 2 obj count per request	175.17 ns/op	173.01 ns/op	1.01
RateTracker 1000000 limit, 4 obj count per request	147.93 ns/op	143.20 ns/op	1.03
RateTracker 1000000 limit, 8 obj count per request	137.04 ns/op	128.82 ns/op	1.06
RateTracker with prune	7.5650 us/op	6.5130 us/op	1.16
array of 16000 items push then shift	5.7604 us/op	5.5294 us/op	1.04
LinkedList of 16000 items push then shift	21.215 ns/op	40.405 ns/op	0.53
array of 16000 items push then pop	296.50 ns/op	297.10 ns/op	1.00
LinkedList of 16000 items push then pop	18.964 ns/op	30.343 ns/op	0.62
array of 24000 items push then shift	8.2777 us/op	8.1109 us/op	1.02
LinkedList of 24000 items push then shift	21.278 ns/op	41.082 ns/op	0.52
array of 24000 items push then pop	262.07 ns/op	252.57 ns/op	1.04
LinkedList of 24000 items push then pop	18.976 ns/op	28.319 ns/op	0.67
intersect bitArray bitLen 8	13.957 ns/op	12.746 ns/op	1.10
intersect array and set length 8	240.18 ns/op	197.35 ns/op	1.22
intersect bitArray bitLen 128	79.023 ns/op	72.182 ns/op	1.09
intersect array and set length 128	2.7660 us/op	2.3526 us/op	1.18
Buffer.concat 32 items	2.3680 ns/op	2.2240 ns/op	1.06
pass gossip attestations to forkchoice per slot	6.6074 ms/op	7.2873 ms/op	0.91
computeDeltas	3.7879 ms/op	4.3001 ms/op	0.88
computeProposerBoostScoreFromBalances	942.23 us/op	890.58 us/op	1.06
altair processAttestation - 250000 vs - 7PWei normalcase	6.2767 ms/op	5.7473 ms/op	1.09
altair processAttestation - 250000 vs - 7PWei worstcase	8.5900 ms/op	8.1202 ms/op	1.06
altair processAttestation - setStatus - 1/6 committees join	256.63 us/op	260.75 us/op	0.98
altair processAttestation - setStatus - 1/3 committees join	477.44 us/op	485.61 us/op	0.98
altair processAttestation - setStatus - 1/2 committees join	679.49 us/op	691.86 us/op	0.98
altair processAttestation - setStatus - 2/3 committees join	918.74 us/op	945.69 us/op	0.97
altair processAttestation - setStatus - 4/5 committees join	1.2747 ms/op	1.3654 ms/op	0.93
altair processAttestation - setStatus - 100% committees join	1.6372 ms/op	1.5584 ms/op	1.05
altair processBlock - 250000 vs - 7PWei normalcase	31.999 ms/op	33.241 ms/op	0.96
altair processBlock - 250000 vs - 7PWei normalcase hashState	49.498 ms/op	44.355 ms/op	1.12
altair processBlock - 250000 vs - 7PWei worstcase	100.57 ms/op	114.80 ms/op	0.88
altair processBlock - 250000 vs - 7PWei worstcase hashState	126.92 ms/op	121.93 ms/op	1.04
phase0 processBlock - 250000 vs - 7PWei normalcase	6.9277 ms/op	5.6303 ms/op	1.23
phase0 processBlock - 250000 vs - 7PWei worstcase	62.147 ms/op	60.875 ms/op	1.02
altair processEth1Data - 250000 vs - 7PWei normalcase	1.1675 ms/op	1.3269 ms/op	0.88
Tree 40 250000 create	1.2432 s/op	1.0784 s/op	1.15
Tree 40 250000 get(125000)	349.93 ns/op	345.64 ns/op	1.01
Tree 40 250000 set(125000)	3.9360 us/op	3.8222 us/op	1.03
Tree 40 250000 toArray()	38.832 ms/op	38.688 ms/op	1.00
Tree 40 250000 iterate all - toArray() + loop	40.153 ms/op	41.141 ms/op	0.98
Tree 40 250000 iterate all - get(i)	145.17 ms/op	146.56 ms/op	0.99
MutableVector 250000 create	18.885 ms/op	21.977 ms/op	0.86
MutableVector 250000 get(125000)	14.780 ns/op	14.795 ns/op	1.00
MutableVector 250000 set(125000)	1.0674 us/op	903.86 ns/op	1.18
MutableVector 250000 toArray()	8.4963 ms/op	8.3745 ms/op	1.01
MutableVector 250000 iterate all - toArray() + loop	9.8068 ms/op	8.5875 ms/op	1.14
MutableVector 250000 iterate all - get(i)	3.6883 ms/op	3.5236 ms/op	1.05
Array 250000 create	7.7897 ms/op	8.2626 ms/op	0.94
Array 250000 clone - spread	3.4225 ms/op	5.9233 ms/op	0.58
Array 250000 get(125000)	1.5770 ns/op	2.1940 ns/op	0.72
Array 250000 set(125000)	1.5480 ns/op	2.0680 ns/op	0.75
Array 250000 iterate all - loop	151.75 us/op	148.93 us/op	1.02
effectiveBalanceIncrements clone Uint8Array 300000	117.72 us/op	278.04 us/op	0.42
effectiveBalanceIncrements clone MutableVector 300000	1.0650 us/op	808.00 ns/op	1.32
effectiveBalanceIncrements rw all Uint8Array 300000	309.62 us/op	308.19 us/op	1.00
effectiveBalanceIncrements rw all MutableVector 300000	279.06 ms/op	227.90 ms/op	1.22
phase0 afterProcessEpoch - 250000 vs - 7PWei	209.07 ms/op	225.28 ms/op	0.93
phase0 beforeProcessEpoch - 250000 vs - 7PWei	101.03 ms/op	86.649 ms/op	1.17
altair processEpoch - mainnet_e81889	603.91 ms/op	700.69 ms/op	0.86
mainnet_e81889 - altair beforeProcessEpoch	171.06 ms/op	189.50 ms/op	0.90
mainnet_e81889 - altair processJustificationAndFinalization	71.115 us/op	66.182 us/op	1.07
mainnet_e81889 - altair processInactivityUpdates	14.151 ms/op	11.552 ms/op	1.22
mainnet_e81889 - altair processRewardsAndPenalties	111.73 ms/op	113.35 ms/op	0.99
mainnet_e81889 - altair processRegistryUpdates	14.271 us/op	17.744 us/op	0.80
mainnet_e81889 - altair processSlashings	3.2820 us/op	3.1610 us/op	1.04
mainnet_e81889 - altair processEth1DataReset	3.6860 us/op	3.6490 us/op	1.01
mainnet_e81889 - altair processEffectiveBalanceUpdates	2.5207 ms/op	2.3984 ms/op	1.05
mainnet_e81889 - altair processSlashingsReset	24.721 us/op	27.180 us/op	0.91
mainnet_e81889 - altair processRandaoMixesReset	25.189 us/op	37.959 us/op	0.66
mainnet_e81889 - altair processHistoricalRootsUpdate	4.4300 us/op	3.8790 us/op	1.14
mainnet_e81889 - altair processParticipationFlagUpdates	15.613 us/op	17.092 us/op	0.91
mainnet_e81889 - altair processSyncCommitteeUpdates	3.1640 us/op	3.6650 us/op	0.86
mainnet_e81889 - altair afterProcessEpoch	218.22 ms/op	212.46 ms/op	1.03
phase0 processEpoch - mainnet_e58758	661.49 ms/op	653.82 ms/op	1.01
mainnet_e58758 - phase0 beforeProcessEpoch	304.04 ms/op	305.33 ms/op	1.00
mainnet_e58758 - phase0 processJustificationAndFinalization	66.588 us/op	68.362 us/op	0.97
mainnet_e58758 - phase0 processRewardsAndPenalties	174.45 ms/op	169.12 ms/op	1.03
mainnet_e58758 - phase0 processRegistryUpdates	33.635 us/op	33.909 us/op	0.99
mainnet_e58758 - phase0 processSlashings	4.0080 us/op	3.5800 us/op	1.12
mainnet_e58758 - phase0 processEth1DataReset	4.2570 us/op	3.7330 us/op	1.14
mainnet_e58758 - phase0 processEffectiveBalanceUpdates	2.1910 ms/op	2.4820 ms/op	0.88
mainnet_e58758 - phase0 processSlashingsReset	22.028 us/op	19.126 us/op	1.15
mainnet_e58758 - phase0 processRandaoMixesReset	26.821 us/op	28.211 us/op	0.95
mainnet_e58758 - phase0 processHistoricalRootsUpdate	4.8050 us/op	4.5070 us/op	1.07
mainnet_e58758 - phase0 processParticipationRecordUpdates	25.956 us/op	21.916 us/op	1.18
mainnet_e58758 - phase0 afterProcessEpoch	183.75 ms/op	181.01 ms/op	1.02
phase0 processEffectiveBalanceUpdates - 250000 normalcase	2.6508 ms/op	2.4895 ms/op	1.06
phase0 processEffectiveBalanceUpdates - 250000 worstcase 0.5	2.8848 ms/op	2.6658 ms/op	1.08
altair processInactivityUpdates - 250000 normalcase	56.829 ms/op	53.171 ms/op	1.07
altair processInactivityUpdates - 250000 worstcase	58.908 ms/op	65.004 ms/op	0.91
phase0 processRegistryUpdates - 250000 normalcase	28.891 us/op	27.427 us/op	1.05
phase0 processRegistryUpdates - 250000 badcase_full_deposits	532.73 us/op	513.98 us/op	1.04
phase0 processRegistryUpdates - 250000 worstcase 0.5	265.86 ms/op	262.77 ms/op	1.01
altair processRewardsAndPenalties - 250000 normalcase	150.79 ms/op	144.23 ms/op	1.05
altair processRewardsAndPenalties - 250000 worstcase	103.03 ms/op	152.93 ms/op	0.67
phase0 getAttestationDeltas - 250000 normalcase	16.890 ms/op	14.562 ms/op	1.16
phase0 getAttestationDeltas - 250000 worstcase	17.756 ms/op	14.644 ms/op	1.21
phase0 processSlashings - 250000 worstcase	6.9875 ms/op	6.4637 ms/op	1.08
altair processSyncCommitteeUpdates - 250000	362.21 ms/op	346.41 ms/op	1.05
BeaconState.hashTreeRoot - No change	624.00 ns/op	629.00 ns/op	0.99
BeaconState.hashTreeRoot - 1 full validator	80.968 us/op	87.090 us/op	0.93
BeaconState.hashTreeRoot - 32 full validator	986.52 us/op	821.87 us/op	1.20
BeaconState.hashTreeRoot - 512 full validator	8.0245 ms/op	7.9976 ms/op	1.00
BeaconState.hashTreeRoot - 1 validator.effectiveBalance	102.67 us/op	104.95 us/op	0.98
BeaconState.hashTreeRoot - 32 validator.effectiveBalance	1.5724 ms/op	1.5879 ms/op	0.99
BeaconState.hashTreeRoot - 512 validator.effectiveBalance	20.308 ms/op	20.905 ms/op	0.97
BeaconState.hashTreeRoot - 1 balances	81.741 us/op	78.552 us/op	1.04
BeaconState.hashTreeRoot - 32 balances	762.97 us/op	748.56 us/op	1.02
BeaconState.hashTreeRoot - 512 balances	7.5904 ms/op	8.5867 ms/op	0.88
BeaconState.hashTreeRoot - 250000 balances	126.15 ms/op	115.96 ms/op	1.09
aggregationBits - 2048 els - zipIndexesInBitList	39.795 us/op	36.041 us/op	1.10
regular array get 100000 times	62.559 us/op	61.746 us/op	1.01
wrappedArray get 100000 times	62.661 us/op	58.216 us/op	1.08
arrayWithProxy get 100000 times	38.866 ms/op	36.817 ms/op	1.06
ssz.Root.equals	622.00 ns/op	589.00 ns/op	1.06
byteArrayEquals	610.00 ns/op	621.00 ns/op	0.98
shuffle list - 16384 els	12.636 ms/op	12.133 ms/op	1.04
shuffle list - 250000 els	185.65 ms/op	178.91 ms/op	1.04
processSlot - 1 slots	18.610 us/op	18.737 us/op	0.99
processSlot - 32 slots	2.4556 ms/op	2.4455 ms/op	1.00
getEffectiveBalanceIncrementsZeroInactive - 250000 vs - 7PWei	500.29 us/op	519.30 us/op	0.96
getCommitteeAssignments - req 1 vs - 250000 vc	5.7980 ms/op	5.3468 ms/op	1.08
getCommitteeAssignments - req 100 vs - 250000 vc	8.4086 ms/op	7.8878 ms/op	1.07
getCommitteeAssignments - req 1000 vs - 250000 vc	8.8159 ms/op	8.3145 ms/op	1.06
RootCache.getBlockRootAtSlot - 250000 vs - 7PWei	9.9100 ns/op	11.390 ns/op	0.87
state getBlockRootAtSlot - 250000 vs - 7PWei	1.4387 us/op	1.4295 us/op	1.01
computeProposers - vc 250000	21.775 ms/op	21.840 ms/op	1.00
computeEpochShuffling - vc 250000	185.80 ms/op	189.66 ms/op	0.98
getNextSyncCommittee - vc 250000	355.97 ms/op	346.43 ms/op	1.03

by benchmarkbot/action

[g11tech]

deployed on unstable dev nodes, all synced up sharing the same EL

validators also attesting (no block proposal yet)

[g11tech]

Block production also looks successful:

[g11tech]

merging since all aspects look good!